optical interference filters - SPOT Imaging Solutions

optical 

interference filters 

For Life Sciences, Machine Vision, Astronomy, Aerospace 

Catalog 2012 

www.omegafilters.com

table of contents 

Introduction................................................................................................................ 4 

About Us.................................................................................................................... 5 

Intellectual Property................................................................................................... 9 

Research & Development.......................................................................................... 10 

Photonics Teaching Kit.............................................................................................. 11 

Descriptions & Nomenclature.................................................................................... 12 

Coating Technology................................................................................................... 14 

Filter Design............................................................................................................. 21 

Coating Process..........................................................................................22 

Physical Vapor Deposition Coatings.............................................................22 

Crystal Monitors Small Crystals....................................................................22 

Optical Monitoring.......................................................................................23 

The Quarter-Wave Stack Reflector...............................................................23 

Multi-Cavity Passband Coating....................................................................23 

Anti-Reflective Coatings...............................................................................24 

Partial Reflector..........................................................................................24 

Dielectric/Metal Partial Reflector and Neutral Density Metal Filters...............24 

Surface Coatings.........................................................................................24 

Dielectric Coatings......................................................................................24 

Extended Attenuation..................................................................................25 

Signal-to-Noise............................................................................................25 

Filter Orientation.........................................................................................25 

Excessive Light Energy................................................................................26 

Angle of Incidence and Polarization.............................................................26 

System Speed.............................................................................................26 

Temperature Effects....................................................................................27 

Transmittance and Optical Density...............................................................27 

Transmitted Wavefront Distortion.................................................................28 

Image Quality Filters....................................................................................28 

Types of Anti-Reflective Treatments and When to Use Them........................................ 29 

Filter Design Considerations and Your Light Source.................................................... 33 

Optical Interference Filters for Applications Using a LED Light Source......................... 35 

Measuring Transmitted Wavefront Distortion............................................................... 36 

Stock and Standard Products – Quick Reference Table............................................... 39 

Analytical Filters....................................................................................................... 44 

Astronomy Filters...................................................................................................... 45 

Amateur Astronomy Filters......................................................................................... 48 

Bandpass Filters....................................................................................................... 49 

Clinical Chemistry and Biomedical Instrumentation Filters.......................................... 53 

Laser Diode Clean-Up Filters..................................................................................... 54 

Laser Edge Longpass Filters...................................................................................... 55 

2 

For current product listings, specifications, and pricing: 

www.omegafilters.com • sales@omegafilters.com 

1.866.488.1064 (toll free within USA only) • +1.802.254.2690 (outside USA)

table of contents 

Laser Line Filters................................................................................................. 57-60 

Laser Rejection Filters.............................................................................................. 58 

Machine Vision Filters.............................................................................................. 61 

3 rd Millennium Filters................................................................................................ 62 

Photolithography Filters............................................................................................ 64 

UV Capabilities........................................................................................................ 65 

Fluorescence Filters Reference Table......................................................................... 66 

Fluorescence Filter Sets Reference Table................................................................... 68 

QuantaMAX and Standard Filters for Fluorescence – Application Note.......................... 69 

QuantaMAX Stock – Fluorescence Filters................................................................... 72 

Standard – Fluorescence Filters................................................................................. 73 

Multi-Band Filters..................................................................................................... 77 

FISH and M-FISH Filters............................................................................................ 79 

FISH and M-FISH Imaging – Application Note............................................................. 81 

Flow Cytometry Filters.......................................................................................... 85-87 

Flow Cytometry – Application Note............................................................................. 85 

FRET Filters.............................................................................................................. 88 

FRET – Application Note............................................................................................ 89 

Pinkel Filters............................................................................................................ 91 

Quantum Dot Filters................................................................................................... 93 

Sedat Filters............................................................................................................. 95 

Ratio Imaging Filters................................................................................................. 96 

IR Blocking and IR-DIC Filters.................................................................................... 96 

Polarizing Filters...................................................................................................... 96 

Neutral Density (ND) Filters....................................................................................... 97 

Beamsplitters & Mirrors............................................................................................ 97 

Multi-Photon Filters.................................................................................................. 97 

Fluorescence Reference Slides.................................................................................. 97 

Microscope Filter Holders......................................................................................... 98 

Optimize Your System with the Right Filter Set – Application Note............................... 99 

Figure of Merit........................................................................................................ 103 

Typical Epi-Fluorescence Configuration.................................................................... 104 

Fluorophore Reference Chart................................................................................... 105 

Emission Color Chart............................................................................................... 108 

Light Sources and Detector Reference Charts........................................................... 109 

Glossary................................................................................................................. 110 

Frequently Asked Questions & Answers.................................................................... 112 

Cleaning Optical Interference Filters........................................................................ 113 

Online Tools........................................................................................................... 114 

General Information................................................................................................ 115 



1.866.488.1064 (toll free within USA only) • +1.802.254.2690 (outside USA) 

3

introduction 

Founded in 1969 by 

Robert Johnson D. Sc., 

President and Technical 

Director, Omega Optical is a 

leader in photonics, exploring new areas with fresh ideas, an 

eager team, and the latest technology to produce the best in 

optical interference filters. 

Our products encompass many markets including; Industrial, 

Commercial, Life Science, Clinical, Astronomy (amateur and 

professional), as well as Defense and Aerospace. We design 

and produce the most diverse offering of interference filters in 

the industry. With over 40 years of experience partnering with 

researchers and instrument designers to meet their requirements, 

we have the experience you need. Along with our experience, we 

bring a corporate commitment to cooperatively explore, understand 

and ultimately refine solutions. This support originates with our 

team of Scientists, Engineers, and Industry experts from various 

scientific fields. We want to be your partner on every project... 

challenging or simple. Our guiding philosophy has always been to 

find solutions. If you need us, call. We will be happy to assist. Toll 

free within the U.S. 866-488-1064 or +1-802-254-2690, sales@ 

omegafilters.com 

Our headquarters resides on the Delta Campus in Brattleboro 

Vermont USA. We encourage you to visit! Our location is in the 

heart of the New England business community, conveniently 

located off Interstate 91; a two-hour drive from Albany New York, 

Boston Massachusetts and Hartford Connecticut. 

If you are currently a customer of Omega 

Optical, thank you! 

If you are new to Omega Optical, 

we look forward to working with you. 

This catalog is representative of only a small portion of products we 

have to offer. The filters within are stock (off-the-shelf) or standard 

(common specifications that are typical of industry standards). 

What’s unique, and not represented in this catalog, is our ability 

to provide custom solutions in a reasonable time frame at typical 

catalog prices from our component inventory. Contact your sales 

representative, or use our online tool, for your filter 

solution. 

Original Equipment Developers and 

Manufacturers 

Our expertise not only lies in the design and manufacturing 

of optical coatings, but in the support we can offer you in the 

development phase of your project. Based on your input, our 

engineering team will design a cost effective solution for the life 

cycle of your instrument. We urge you to contact us in the early 

development stage of your project. Our goal is to assist you in 

finding a solution that will achieve maximum system efficiency at 

the lowest cost. We will work closely with you through all steps, 

proof-of-concept, bread-boarding and prototyping to ensure the 

development of an optical solution that is consistent with your 

expectations. 

We regard our relationship with you as a long-term partnership. 

Our support will continue into the production phase of your project. 

Research Scientists and Engineers 

Whether your lab or research project requires one or several 

interference filters we invite you to contact our technical sales 

team. We will assist in finding the right solution whether it is an 

off-the-shelf product, a semi-custom solution, or a filter custom 

manufactured to your requirements. 

Stock interference filters are available off the shelf at competitive 

prices. 

Semi-custom solutions from our extensive inventory of overstock 

filters or plate stock configured to your requirements can be 

processed and shipped to you in 5 business days. 

Custom solutions are specifically produced to your requirements. 

Our sales team will work with you to develop the most cost effective 

solution for your application. 

4 




about us 

Collaboration 

In any instrument development project, collaboration is key. 

Involving Omega early in the system design process results in 

optimized filter design before the system specifications become 

fixed. The result is reduced costs and improved performance. 

For these reasons, free flow of information is critical. To protect 

trade secrets, we ensure confidentiality throughout the life of the 

project. As the process unfolds, crucial performance features are 

identified, proof-of-concept filters are supplied for breadboarding 

needs, and beta parts are produced meeting the established 

requirements. With the completion of the development phase, 

we have demonstrated and provided a manufacturing plan 

that can be repeatedly executed for your specified production 

requirements. 

System/Instrument Development 

From many years of partnership experience with the world’s leading 

OEMs, we have developed a comprehensive understanding of the 

needs of instrument developers and one of the largest ranges 

of capabilities and product lines in the thin-film industry. A 

collaborative engineering approach results in high signal-to-noise, 

application optimization, responsive prototyping, and rapid timeto-market 

cycles. 

Throughout the design process our engineering and sales staff 

works with your development team to optimize total system 

performance within time and budgetary guidelines. 

Following “proof-of-concept,” breadboarding, and prototyping, a 

developed design is translated into an optimized manufacturing 

plan for production. An effective plan takes into account 

performance specifications, as well as yield maximization, product 

uniformity, and cost targets. Projections are then used to create 

delivery schedules to address critical inventory requirements. 

Review of manufacturing plans on a regular basis results in the 

integration of continuous improvements for your project. 

Custom Solutions 

Standard catalog products can provide a high velocity filter 

solution with reasonable performance and, as a result, can 

be used for R&D, proof-of-concept, and breadboarding. For 

optimum system performance and significantly reduced cost we 

strongly recommend collaborative engineering and customized 

filter solutions for your specific instrument and application. 

Custom Filters Overview 

Custom filters are available in wavelengths from 185nm in the UV 

to 2500nm in the IR. There are a variety of filter types including 

bandpass, narrowband, wideband, longpass, shortpass, edge, 

rejection band, beamsplitters, mirrors, and absorption glass. Filters 

can be manufactured to almost any physical configuration up to 

200mm round. 

Omega has developed a number of programs to service the custom 

filter needs and requirements of OEM instrumentation customers 

and researchers. 

Engineering Services Overview 

Omega Optical’s engineering services are founded on years 

of technical experience, proprietary software, and custom 

modified optical measurement instruments. Our engineers play 

a collaborative role in design teams, assembled to develop 

prototype instruments, and are experienced at optimizing system 

performance. For sub-assembly engineering and manufacturing, 

our design and manufacturing services include interference filters; 

optical components; and customized rings, holders, and mounting 

hardware. Further, the R&D group develops both new coatings, 

and novel applications of optical filters. These applications include 

biomedical scanning, pathogen detection, and photovoltaic stacks. 

Partnership 

For more than 40 years we have been the filter supplier of choice 

to hundreds of system manufacturers. This stands as testament to 

our high technical standards, the ability to produce thousands of 

parts to identical specifications, and timely delivery. Throughout 

these long-term partnerships we build your confidence to become 

your sole supplier. A relationship is based on intimate knowledge 

of your instrument, and team that leads to increased efficiencies 

and instrument performance over time. 




5

about us 

MARKETS & APPLICATIONS 

Life Science 

Omega Optical is a leading supplier worldwide of custom filters 

for research, clinical, and point-of-care fluorescence based 

instruments and applications. We service the world’s leading 

system manufacturers and have developed one of the largest 

ranges of capabilities and product lines in the industry. Our filters 

are used extensively in research and clinical applications in the 

biomedical, biotech, and drug discovery markets, with filters being 

engineered into the next generation of life science instruments. 

Representative Markets include: 

• Microplate and MicroArray Readers and Scanners 

• DNA Sequencers and Analyzers 

• Lab-on-a-Chip and Gene Chip Readers 

• Flow Cytometers and Cell Sorters 

• Real-time PCR Analyzers 

• Gel Documentation Readers 

• Scanners and Imaging Systems 

• High-Throughput and High-Content Systems 

• Genomics and Proteomics Systems 

• Fluorescence and Raman Spectroscopes 

• Confocal and Multiphoton Microscopes 

Fluorescence Microscopy 

We have played a pioneering role in the developments of filter 

technology for fluorescence microscopy and are one of the world’s 

leading suppliers in this market. We offer an extensive product line 

of dye-specific filter sets for single and multi-label fluorescence 

microscopy applications and work collaboratively with researchers, 

labs, and microscope manufacturers on the development of sets 

for new cutting-edge applications. Filter sets, individual filters, and 

holders are available for all major microscope manufacturers and 

models, including Leica, Nikon, Olympus, and Zeiss. 

Representative Applications: 

• Confocal 

• Multiphoton 

• Fluorescent Proteins 

• Quantum Dots 

• M-FISH 

• FRET 

• Ratio Imaging 

• Caged Compounds 

Astronomy/Aerospace 

We are one of the most respected suppliers of optical filters in the 

world for space-based and observational astronomy and aerospace 

projects. We work in collaboration with NASA, JPL, AURA, 

ESO as well as a variety of international consortia, government 

agencies, and researchers. We have years of experience designing 

and manufacturing custom and standard prescription filters to 

the highest imaging quality standards. Our capabilities include 

solar observation, photometric sets encompassing Bessel, SDSS, 

Stromgren, and other filters. 

Our filters have helped probe deep space as part of the Hubble 

Space Telescope’s Widefield Planetary Camera and served as the 

eyes of the Mars Exploration Rovers. See pages 45-47. 

Photolithography 

Our i-line filters for semiconductor lithographic tools, such as LSI 

and LCD Steppers, surpass the performance of standard OEM filters. 

These high performance and environmentally stable bandpass filters 

resolve monochromatic wavelengths from the high power Metal 

Halide/Mercury lamps reaching the photomask substrate, so that 

optimum resolution is achievable. We also supply superior maskaligner 

filters for the lithographic process. See page 64. 

Color Imaging 

Color imaging systems benefit from the use of precision optical 

filters which control the spectral properties of light and color 

separation to exacting tolerances. Image capture and reproduction 

are enhanced when the prime colors of light are precisely separated 

or trimmed on capture and then recombined before reaching the 

detector. Image quality and performance improves when system 

optics deliver precise color separation, high color signal-to-noise, 

and a wide dynamic range. Omega offers a variety of products to 

this market, including a patented color enhancement filter, as well 

as color separation, color correction, and color temperature filters. 

See pages 16-18. For detailed product specifications, please visit 

our website. 

Raman Spectroscopy 

Raman spectroscopy is employed in many applications, including 

mineralogy, pharmacology, corrosion studies, analysis of 

semiconductors and catalysts, in situ measurements on biological 

systems, and single molecule detection. While this technique 

provides positive material identification of unknown specimens to a 

degree that is unmatched by other spectroscopies, it also requires 

rigorous filter specifications for the detection and resolution of 

narrow bands of light with very low intensity and minimal frequency 

shift relative to the source. To meet these requirements Omega 

supplies a variety of products, including laser line filters for 

“cleaning up” laser signals and high performance edge filters that 

out-perform holographic notch filters. 

Industrial Instrumentation 

Industrial instrumentation requires precision filters for control, 

analysis, and detection. We provide a wide variety of filter solutions 

for various industrial applications that includes some of the following: 

Process Control and Monitoring; End Point Determination; Closed 

Loop and Real-time Instruments; Materials Analysis; and others. 

6 




Capabilities 

Design 

• Thin Film DesignSoftware 

• TF CALC 

• Optilayer (Leybold) 

• FilmStar 

• The Essential Macleod 

• Optical Raytrace Software 

• Mechanical CAD Packages 

• Instrumentation Interface Tools such as LabView and Python 

• Chemical modeling with Hyperchem 

Optical Testing 

• Spectrally Resolved Measurements of Transmission, 

Reflectance, and Absorption: 

- Multiple Spectrophotometers 

- A Spectrophotometric Mapping System for large substrates 

- Attachments for off-axis R&T Measurements including 

Polarization Effects 

• Optical Density Measurements: 

- Visible Laser Radiometers 

- NIR Laser Radiometers 

• Surface Quality (total wavelength distortion, flatness, 

wedge, roughness, and pinhole density): 

- Broadband Achromatic Twyman-Green Interferometer 

- Shack-Hartmann Wavefront Tester 

- Autocollimator 

- Integrating Sphere 

- Angle Resolved Scatter Test Set 

- Differential Interference Contrast (DIC) Microscopy 

• Fiber Optic Testing at Visible and Near Infrared 

Wavelengths 

• Fluorescence and Autofluorescence: 

- Spectrofluorimeters 

- Multispectral Fluorescence Imaging 

• Environmental Testing: 

- Low and High Temperature Testing 

- Humidity Testing 

• Photovoltaic Testing: 

- IV/CV Profiles 

- Kelvin Probe 

Coating Systems 

Of our numerous vacuum coating systems, we have the capability 

for coating a full range of dielectric metal and insulation materials. 

We achieve physical vapor deposition (PVD) (evaporated coatings) 

with or without ion assist (IAD) of refractory oxides, as well as 

thermal evaporation of metal salts and metal alloys. All of our 

coating systems have been designed to enhance our proprietary 

coating processes. 

Optical Fabrication 

• CNC Metal Machining 

• Scribe & Break 

• Laser Scribing, Welding, and Ablation 

Our glass fabrication shop is equipped with a Speedfam grind and 

polish machine, along with diamond-tooled machines, including 

CNC drills, shapers, and saws. 

Scribe and break 

For the best competitive price and reduced lead times, our 

scribe and break capabilities make use of a unique diamond 

wheel cutting technology. Scribe and break is a clean process 

that does not require oils, blocking waxes, or exposure to heat. 

Additionally there is significantly less handling of the optical coated 

plate. Fundamentally, we scribe the exact shape of the finished 

product penetrating through the optical coating on the substrate 

material. Scribes may be generated with a depth up to 90% of 

the material thickness greatly reducing a required breaking force. 

This technology is useful over a wide range of substrate material 

thicknesses from .05 mm to upwards of 3 mm. 

The end results of this capability include consistent outcome, 

higher yield, increased edge strength, rapid dicing, and a 

reduction of potential edge chipping and cracks. Cutting accuracy 

is very high enabling the production of very small finished 

product. Additionally, the ability to hold very tight tolerances as 

well as produce more unusual, irregular, or non-standard shapes 

becomes available. 

Optical Assembly 

Our fully equipped machine shop has the capability of producing 

jigs and fixtures along with a variety of custom filter rings, wheels, 

and holders. 

Filter components are cleaned ultrasonically and assembled under 

laminar flow hoods. 

Glass Substrates 

We stock nearly all scientific glasses, fused silica, and specialty 

glass substrates. 




7

about us 

Quality Assurance, Testing, and Certification 

The Quality Management System of Omega Optical is modeled 

on the foundations of the ISO 9001:2000 quality management 

standards. 

The overall company goal is to enhance product quality with 

standardized and systematic methods. 

Filters are tested and evaluated at every stage of production. 

Spectrometers and optical measuring instruments are tested, 

controlled, calibrated, and maintained to meet the requirements 

of our quality system. 

• Filter surface durability and quality is in accordance with MIL- 

C-48497A. 

• Environmental durability, testing documentation and certification 

can be provided at the customer’s request. 

• When appropriate, we follow sampling procedures defined by 

MIL-STD-105E. 

• REACH, PFOS and RoHS statements can be found on our 

website. 

We have an in-house capability for making automated spatiallyresolved 

spectral measurements of coated plates up to 200 mm 

in diameter. These high-resolution spatial-spectral measurements 

quantify in-spec regions of each plate; the result is fed directly 

to downstream part 

configuring operations. 

Plate regions that do 

not meet spec are 

inventoried for future 

sale requiring no 

"Omega Optical will deliver quality 

product on time, which meets or 

exceeds customer expectations, 

through continual improvement 

and effective partnerships with 

suppliers and customers." 

additional spectral 

measurements. This 

one-stop measurement of the entire plate eliminates redundant 

measurement and drastically increases efficiency both in plate 

utilization to meet immediate orders and future data mining 

operations to locate surplus stock. 

Personnel 

A technical staff of engineers, industry specialists, scientists, PhDs, 

and technicians combine years of experience, a broad knowledge 

base, and a command of the craft involved in producing precision 

interference filters. 

8 




intellectual property 

3 RD Millennium filters are available as high-performance commodity filters for OEM instrumentation or for research and lab applications. 

Patent #6,918,673 

SpectraPlus for accurate hue, enhanced saturation, increased color signal-to-noise, and a resulting improved Modulation Transfer 

Function (MTF). SpectraPLUS coating technology is the deposition of multiple layers of thin film coatings on glass and acrylic lenses for the 

enhancement of viewing color images to address two primary areas. This technology benefits color imaging systems as well as applications 

where the eye is the detector. The coating allows transmission of the three bands of pure color—red, green, and blue—while blocking those 

intermediate wavelengths that distort the perception or recording of color. It also eliminates wavelengths in the ultraviolet and near infrared 

which are detrimental to an accurate color rendering and visual record. Patent #5,646,781 

Multispectral stereographic display system Patent pending 

Multispectral stereographic display system with additive and subtractive techniques Patent pending 

ALPHA coating technology 

Omega Optical’s proprietary ALPHA coating technology for extremely steep slopes resulting in precise edge location, the ability to place 

transmission and rejection regions exceptionally close together, and high attenuation between the passband and the rejection band. ALPHA 

coating technology pushes the limits of fluorescence and Raman signal detection, producing extremely high signal-to-noise and brighter 

images for demanding imaging applications. 

Multi-band Technology 

Omega Optical holds the 1992 patent on all filters with multiple passband and rejection bands, including dual-band, triple-band, and quadband 

filters. These filter types have usefulness in a variety of life science applications for visualizing multiple fluorophores simultaneously, as 

well as in a range of other applications. Patent #5,173,808 

Multispectral Imaging 

Omega Optical licenses and owns IP related to high speed systems for multispectral imaging of tissue. Our filters are used within a device, 

which has many applications in the biomedical optics field. 

Organic Photovoltaics 

Omega Optical owns IP related to organic photovoltaic devices. Our thin film expertise is leveraged to fabricate these devices, which have 

significant potential in the alternative energy field. 




9

esearch & development 

We embrace a vision that goes beyond designing and fabricating state-of-the-art interference filters. Most bandpass, 

longpass and shortpass interference filters are based on the real component of the refractive index of dielectric materials. 

At Omega Optical, our R&D team is developing novel thin films where the refractive index has both a real and a complex component. 

Examples include semiconductors (such as p-type organics, & n- 

type organics), and transparent conductive oxides (such as indiumtin-oxide, 

& aluminum-zinc-oxide). The complex component of the 

index of these materials can lead to absorption and/or reflectance 

in specific spectral bands. In addition, we are depositing dielectric 

stacks on unusual substrates, such as the tips of optical fibers. Our 

team includes expertise in optical sciences, physics, chemistry, 

materials science, electrical engineering, mechanical engineering, 

bioengineering, and software (3 PhDs, 1 MS, and 3 undergraduate 

degrees). We focus on leveraging our expertise to create products 

that rely on advanced thin films. Currently, we are addressing two 

key areas: solar conversion and multispectral scanning. 

Omega Optical’s Solar Conversion program employs organic 

thin film absorbers, and electrodes composed of transparent 

conductive oxides. Our solar goal centers on creating a solar 

cell prototype enabling significant reductions in module cost and 

significant increases in module efficiency, leading to acceptable 

payback times. This objective will be addressed by integrating 

photovoltaic (PV) and/or photothermal (PT) collection mechanisms 

while avoiding both scarce and toxic materials. The potential of low 

cost organic PV materials has not been widely realized because of 

low efficiency relating to electronic mobility and excitonic diffusion 

lengths. We believe that organic thin film deposition parameters 

can be adjusted to optimize these parameters and maximize PV 

efficiency. Further, organic materials can be configured to harvest 

multiple spectral bands. We plan to separate these bands via costeffective 

spectral splitting for efficient collection by the appropriate 

material. Ultimately, we plan to integrate our designs with residential 

and commercial building materials. Targeted products include 

semitransparent solar windows. 

This effort has been co-funded by Omega Optical Inc. and 

the United States Department of Energy. 

Left to Right: Dr. Robert Johnson – President and Technical Director - 

Omega Optical; Patrick Leahy - United States Senator, Vermont; Dr. Gary 

Carver - Director of R&D - Omega Optical. 

fast fiber based spectrometer. This project leverages several of our 

interference filter designs deployed in the fluorescence market 

since the last 1980’s. 

Ultimately, biomedical researchers will use this new technology to 

catalog extensive libraries of multispectral images showing tumor 

angiogenesis and subsequent metastases. These enhanced libraries 

will lead to several applications in pathology labs, oncology 

labs, and clinics. Clinicians will use the technology to take optical 

biopsies, perform treatments, and monitor long-term results. 

Patients will have access to real-time diagnosis and treatment. Surgeons 

will be able to optimize surgical margins, extending the lives 

of many cancer victims. Targeted products include disease-specific 

fiber cassettes for use in customized confocal scanning systems. 

This project is funded by a Phase II SBIR grant from the National 

Cancer Institute within the National Institutes of Health in Bethesda 

Maryland USA. 

Omega’s Multispectral scanning program project integrates 

interference filters, fiber Bragg gratings, and optical fibers. This 

fiber based design enables high speed spectral management, 

providing medical diagnoses in real-time. Our biomedical goal 

centers on developing a high-speed fiber optic based optical 

spectrum analyzer (OSA) that can enable real time multispectral 

imaging of cancer at the cellular level. Existing technologies have 

not combined sufficient spatial, spectral, and temporal resolution 

in one instrument. Standard spectrometer acquisition speeds are 

not fast enough to generate multispectral data at rates that avoid 

spatial impairments due to the movements of living biological 

samples. The central innovation in this effort is that spectra can 

be acquired for each pixel in a confocal spatial scan by using our 

Technical Outgrowths 

The above projects are generating results that are finding additional 

applications including customized transparent conductive oxides, 

and thin film spectral blocking layers with low wavefront distortion. 

We also see potential in applications in such as food & water testing, 

pharmaceutical product screening, multispectral microscopy, 

and flow cytometry. Further, we have developed a suite of optical 

testing capabilities that are available on a consulting basis. 

Optical solutions can be employed in a multitude of applications 

from creating alternative energy solutions to new methods for treating 

cancer. We encourage you to inquire regarding other novel optical 

methods that will improve the quality of life throughout the world. 

10 




photonics teaching kit 

Involved in the design, fabrication, or production of optics or 

optical devices? 

Teaching or learning about photonics? 

Learn principles of photonics and how the interaction of 

light with matter plays a role in our everyday lives. 

Get a head-start on the exciting careers of tomorrow. 

Hands-on labs examine a wide variety of topics within 

photonics. 

One Photonics Kit accommodates 6 small groups. 

Photonics now and in the future begins with the educational systems of our society. 

The Omega Optical Photonics Kit – Teach Photonics! 

For Science Educators – Help students to explore the environment around them, discovering the principles on the interactions of light 

and matter and how to manipulate these interactions. 

For Professionals – Finding workers with a fundamental understanding of optical principles is a challenge. The need for cost-effective 

employee training and education that delivers real-time benefits is a priority as organizations continuously adapt to changing marketplaces, 

and external competition. 

Our Photonics Teaching kit includes 12 lab activities based on various topics within the field of photonics including solar cells, reflection, 

refraction, wave interference, LEDs, light detection, complementary colors, fluorescence, and phosphorescence. 

The comprehensive labs are organized and supported 

with all required hardware for the following: 

wave/particle duality of light 

interactions of light and matter including scattering, reflection, 

refraction, fluorescence and phosphorescence 

relationship between the electronic structure of an atom or 

molecule and its emission and absorption spectra 

how light can be used to encode information by changing 

intensity, spectral characteristics or polarization 

how information about the structure of a molecule can be 

elucidated using spectroscopy 

principles behind optical computing 

human and animal perception of color 

principles behind the operation of LEDs, solar cells, and fiber 

optic cables are explored 




11

Descriptions & Nomenclature 

Bandpass Filters 

Dichroic Filters 

555XX30 

CWL (center wavelength) Filter Design FWHM/Bandwidth 

3RD550-580 

Cut-on Cut-off 

505DRLP 

Cut-on Filter Design 

675DCSPXR 

Cut-off Filter Design 

Note: Full Width Half Max (FWHM) is defined 

by the region of the passband where the transmission 

of the filter is 50% of the maximum transmission. 

Filter Design – Our nomenclature and descriptors define the 

performance characteristics of filter designs. 

• BP – Bandpass filter: Bandpass filters transmit light within a 

defined spectral band. Coating designs range from 2 to 6 cavities. 

• QM – QuantaMAX: Surface coated, single substrate designs 

provide steep edges, very high transmission and minimal 

registration shift. 

• 3RD – 3 RD Millennium: Filters are manufactured using 

proprietary ALPHA coating technology and Omega’s patented, 

hermetic assembly, and defined by the critical cut-on and cut-off 

requirement. 

• AF – ALPHA Filter: Alpha filter designs are manufactured using 

Omega’s proprietary technology resulting in extremely steep 

edges, precise edge placement, and theoretical attenuation 

>OD10. Defined by the critical cut-on and cut-off requirement. 

• DF – Discriminating Filter: These filter designs have 6 or more 

interfering cavities, resulting in a rectangular bandpass shape, 

very steep edges, and very deep blocking up to optical density 

(OD) 6 outside the passband. 

• WB – Wideband Filter: Wideband filters are 4 & 5 cavity 

designs with FWHM greater than 30nm, up to several hundred 

nanometers. 

• NB – Narrowband: Narrowband filters are 2-cavity designs with 

FWHM typically between 0.2 and 8nm. 

Note: Cut-on or cut-off wavelength is defined 

as the wavelength at which the dichroic is at 50% 

of its maximum transmission. 

Filter Design – Dichroics are filters that highly reflect one specified 

spectral region while optimally transmitting another. These filters 

are often used at non-normal angles of incidence, typically 45 

degrees. 

• DC – Dichroic: These filters provide wide regions of both 

transmission and reflection, exhibiting a high degree of 

polarization along with a somewhat shallow transition slope. 

• DR – Dichroic Reflector: These designs provide a steeper 

slope than typical DC filters, low polarization, a wide range of 

transmission and a limited region of reflection. 

• DCXR – Dichroic Extended Reflector: A design that provides 

extended reflection regions. 

• DCSP / DCLP / DRSP / DRLP: These designations dictate those 

portions of the spectrum that will be transmitted and reflected. 

The “SP” (shortpass) nomenclature means the filter will be 

transmitting wavelengths below the defined cut-off region. The 

“LP” (longpass) nomenclature defines the region of transmission 

as wavelengths above the defined cut-on region. 

12 




Longpass & Shortpass Filters 

515ALP 

Cut-on Filter Design 

680 ASP 

Cut-off Filter Design 

3RD 650LP 

Filter Design Cut-on 

Note: Cut-on or cut-off wavelength is defined 

as the wavelength at which the filter is at 50% 

of its maximum transmission. 

Filter Product Line Codes 

XA – Analytical Filters 

XB – Bandpass Filters 

XC – Microscope Filter Holders 

XCC – Clinical Chemistry 

XCY – Flow Cytometry Filters 

XF – Fluorescence Filters 

XL – Laser Line Filters (not blocked) 

XLD – Laser Diode Clean-up 

XLK – Laser Line Filters (fully blocked) 

XLL – Laser Line Filters 

XMV – Machine Vision 

XND – Neutral Density Filters 

XRLP – Raman Longpass Filters 

XUV – UV Filters 

• LP – Longpass: These filters transmit wavelengths longer than 

the cut-on and reflect a range of wavelengths shorter than the 

cut-on. 

• SP – Shortpass: These filters transmit wavelengths shorter than 

the cut-off and reflect a range of wavelengths longer than the 

cut-off. 

Multi-band Filters 

• DB – Dual Band: Filters are designed to have two passbands 

and two rejection bands. 

• TB – Triple Band: Filters are designed to have three passbands 

and three rejection bands. 

• QB – Quad Band: Filters are designed to have four passbands 

and four rejection bands. 




13

Coating Technology 

QuantaMAX – for high performance interference 

filters 

Outstanding spectral characteristics on a wide variety of 

substrate materials utilizing our state-of-the-art deposition 

technology, Dual Magnetron Reactive Sputtering (DMRS). 

Transmission 

For today’s most sensitive instruments, 

QuantaMAX optical coatings provide 

exceptional throughput. As seen in Figure 1, a 

standard 510-560 interference filter achieves 

transmission in excess of 97%. Combined with 

deep out of band attenuation, QuantaMAX 

optical coatings make every photon count. 

Transmission (%) 

Wavelength (nm) 

Optical Density 

For many applications, the out of band 

blocking at the detector is as important as the 

overall transmission. Figure 2 shows the out 

of band blocking from 300-1000nm and the 

optical density average of > 6.0. A filter with 

these characteristics operating in a system 

with an ideal light source and detector could 

be expected to have a signal/noise ratio of 

exceeding 10,000:1, while collecting all 

available signal. 



14 




Lot to Lot Reproducibility 

With the Dual Magnetron Reactive Sputtering 

(DMRS) process, QuantaMAX optical coatings 

employ the latest methods in optical thin-film 

design and deposition control. Utilizing the 

DMRS technology we achieve very precise 

individual layer thickness, along with forward and 

backward “proof-reading” of layer execution, 

leading to a high degree of predictability and 

reproducibility lot-to-lot. As depicted in Figure 3, 

the edge of the 650-670 bandpass filter varies 

only 1 nm in either the cut-on or cut-off edges 

across a sampling of 5 individual deposition lots. 

Transmission Transmission (%) Transmission (%) (%) 




Minimized Transmission 

Band Distortion 

The ability to precisely deposit a layer of coating 

material of optimized optical thicknesses in 

a stable and highly reproducible manner 

throughout the deposition cycle provides 

excellent transmission characteristics with 

minimal pass-band rippling. Figure 4 and 5 

show the typical performance of long-pass and 

short-pass interference filters. 

Transmission Transmission (%) (%) (%) 




Transmission (%) (%) 

Wavelength Wavelength (nm) (nm) 





15


Viewing Enhancement Coatings 

SpectraPlus for accurate hue, enhanced saturation, increased 

color signal-to-noise, and a resulting improved Modulation Transfer 

Function (MTF). SpectraPLUS coating technology is the deposition 

of multiple layers of thin film coatings on glass and acrylic lenses for 

the enhancement of viewing color images to address two primary 

areas. This technology benefits color imaging systems as well 

as applications where the eye is the detector. The coating allows 

transmission of the three bands of pure color—red, green, and 

blue—while blocking those intermediate wavelengths that distort the 

perception or recording of color. It also eliminates wavelengths in the 

ultraviolet and near infrared which are detrimental to an accurate 

color rendering and visual record. 

Two of the more recent and unique technical capabilities developed 

at Omega have been employed in developing these products. They 

offer the ability to deposit complex coatings on curved surfaces with 

control of the thickness distribution over the full usable aperture of 

the curved optic that makes these features possible. The control 

of thickness can be either to create uniform thickness where the 

normal distribution is thinner away from the center, or it can be 

applied and adjusted to create a thickening coating profile toward 

the edge to compensate for viewed angular effects that would cause 

band shifting. 

Other enhancements can be integrated into viewing systems. 

Coatings such as photochromics, or anti-scratch, or hydophobic 

can be added to produce the highest technology, and performing 

eyewear world-wide. Applications where these coatings can make 

the difference between success and failure exist everywhere that 

excellent vision is a benefit. Typical of these would be dentistry, 

surgery, sports, high speed maneuvering and viewing in poorly lite 

situation. 

Omega Optical is prepared and anxious to work closely to refine this 

product line to bring your offer to be the last considered. 

SpectraPLUS is protected by U.S. patent #5,646,781. 

Depth Defining ® series is a totally new approach to displaying and 

viewing an image with an X and Y impression as well as a clear Z 

element. The ultra-complex spectral function divides the visible into 

two visually identical white mixtures which are mutually exclusive. 

The left and right viewing eye see distinct images that have been 

projected spatially or temporally independent. The result is an image 

with depth that the viewer can experience with clarity. 

Both of these product developments open many possibilities for 

new areas of optical device improvement and development. 

Photo courtesy of Leybold Optics. Syrus Pro 1510 LION Assisted Electron 

Beam Custom Opthalmic Coater. Our engineers have worked closely 

with Leybold Optics of Germany to refine the performance of this large 

coating tool for the precise deposition of complex multi-layers for Image 

Enhancement coatings under the SpectraPlus brand. 

16 




ColorMAX series is intended for spectral refinement with the 

intended purpose of improving color rendition through saturation and 

hue. Curved lenses are coated with a complex multi-layer coating 

that removes harmful UV rays, as well as IR. These coatings further 

eliminate the colors of light that stimulate multiple cones that result in 

color confusion. The final product is eyewear that forces all colors to 

explode from their background. 

We offer two ColorMAX filters with SpectraPLUS coatings; XB29 is 

optimized for digital imaging sensors and XB30 is optimized for the 

human eye and film. All filters are finished to the highest imaging 

quality standards and are available in stock and custom sizes. 

XB29 for Digital Imaging Systems and CCD based cameras blocks 

the crossover regions between blue/green and green/red centered at 

490nm and 600nm respectively. To prevent IR saturation of siliconbased 

sensors, the coating provides a high degree of attenuation in 

the near infrared region, from 750nm to 1100nm. XB29 also offers 

complete attenuation of ultraviolet A and B, and deep blue up to 

430nm. 

For Digital Imaging Systems: 

- Commercial Printing Industry: 

Pre-press Scanners 

- Machine Vision Industry: 

Camera and Lens Systems 

- Office and Home Small Equipment Industry: Desktop Scanners, Color 

Copiers, Digital Copiers. 

- Photography/Video/Film Industry: 

Video & Digital Cameras and Lenses, Photo Scanners 

- Remote Sensing: Camera Systems 

XB29 for Eye and Film is optimized for applications where the human 

eye or photographic film is the detector. Color imaging is enhanced 

with increased saturation, accurate hue, and improved contrast and 

resolution. This version of the SpectraPLUS filter has two stop band 

regions centered at 490nm and 580nm for blocking the prime color 

"crossover" wavelengths between blue/green and green/red in the 

visible spectrum. The XB30 offers high attenuation of ultraviolet A & 

B. It also attenuates the near infrared in a band centered at 725nm 

For Human Eye and Photographic Film Detection: 

- Sports Eyewear Industry: Sunglasses, 

Ski Goggles, Active Sports Glasses 

- Lighting Industry: Medical and Dental Lights, Bulb and Reflector coatings 

- Photography/Video/Film Industry: 

Camera Lens, Video, Film and Slide Projectors, Color and Black&White Film 

Printers, Enlarger Lens 

- Sports Optics Industry: Binoculars and spotting scopes, Rifle Scopes 

All sensors - human eye, film, and electro-optical - have limitations in 

how they "see" and record color. Their receptors significantly overlap, 

as do the wavelengths for the three prime colors of light: red, green, 

and blue. A photon of light from within this overlap region can leave an 

incorrect signal on the receptor so that a green photon, for example, 

can be perceived or recorded as blue or red. 




17


Transparent Conductive Oxides Overview 

Transparent Conductive Oxides (TCOs) are a special class of 

materials that exhibit both transparency and electronic conductivity 

simultaneously. These materials have widespread applications in 

flat-panel displays, thin film photovoltaics, low-e windows, and 

flexible electronics. The requirements of the these materials are not 

just limited to transparency and conductivity but also include work 

function, processing and patterning requirements, morphology, 

long term stability, lower cost and abundance of materials involved. 

Spectral edges can be generated with the intrinsic properties of one 

layer of TCOs. This happens with materials like Indium Tin Oxide 

(ITO) and Aluminum Zinc Oxide (AZO) that have much stronger k 

values in one spectral band than another band. 


Description 

Currently, ITO is far superior in performance compared to other 

TCOs and many efforts are being made worldwide to find suitable 

alternatives. ITO intrinsically has high transparency in the visible 

and high reflectance in the infrared region. It is commonly used in 

LCDs and thin film photovoltaic devices. Characteristics of these 

materials can be widely altered with making changes in deposition 

parameters. These materials can be integrated with dielectrics to 

provide wide band IR blocking with thinner layers and low wavefront 

distortion. 

Types 

Addressing the wide concern about scarcity and high cost of 

Indium, Omega is also investigating several other Indium free 

TCOs, namely, 

• Aluminum doped Zinc Oxide 

• Fluorine doped Tin Oxide 

• Zinc Tin Oxide 

• Nickel Oxide and other combinations. 

Documentation: Spectrophotometric trace of the attenuation, cuton, 

and transmission regions provided. Electronic characteristics 

such as work function, resistivity and surface roughness are 

provided upon request. 

Figure X: Typical ITO Spectral Curve 

Curve shows the intrinsic characteristic of ITO to transmit in the visible and 

reflect like a metal in the IR region. The cross-over frequency (near the 

plasma frequency) can be moved with changes in deposition parameters. 

Specifications 

Average Transmission 

> 80 % in the visible 

Reflectance 

High in the IR region 

Temperature of Measured Performance 20°C 

Operating Temperature Range - 60°C to + 80°C 

Humidity Resistance 

Per Mil-STD-810E, Method 507.3 Procedure I 

Coating Substrates 

Optical quality glass 

Surface Quality 

80/50 scratch/dig per Mil-O-13830A 

Sheet Resistance 

5-1000 ohms/sq 

Surface Roughness 

Compatible with the Application 

Sizes 

Custom dimensions 

Barrier Layer 

Silicon Dioxide 

Process 

Ion Assisted Magnetron Sputtering 

Work Function 

Variable over 4-6eV 

In addition to standard specifications, we also 

produce customized TCO coatings on various kinds 

of surfaces for many applications. 

18 




Organic Semiconductor Overview 

Organic materials have been used as standard pigments for over 

100 years in dyes, inks, food colors and many plastics. One class 

of organic materials, aromatic hydrocarbons, are known for their 

stability, insolubility in water and reduces tendency to migrate into 

other materials. These compounds also exhibit semiconductive 

properties. Spectral edges can also be generated with the intrinsic 

properties of organic semiconductors. This is achieved with 

materials like Copper Phthalocyanine (CuPc) that have a strong k 

peak in the visible region caused by the so-called Q-band. 

Description 

Organic materials are commonly used in OLEDs, Organic 

Photovoltaic Devices and Organic FETs. Research is being done 

worldwide to make these devices commercially available. These 

materials have significant absorption peaks in the visible and have 

high transmission in the infrared region. As a result, they can be 

integrated with other materials to provide blocking with thin layers in 

optical filters. Other forms of metal-phthalocyanines and perylene 

derivatives have absorption peaks in different regions of UV, Visible 

and NIR regions. 


Figure Y: Copper Phthalocyanine Transmission 

Typical transmission of CuPc that has significant absorption peak in visible 

and transmits in IR region. 


Blocking 

100-150nm wide peaks in visible region 

Average Transmission 

> 80 % in the IR region 

Temperature of Measured Performance 20°C 

Operating Temperature Range - 60°C to + 80°C 

Humidity Resistance 

Per Mil-STD-810E, Method 507.3 Procedure I 

Coating Substrates 

Optical quality glass 


80/50 scratch/dig per Mil-O-13830A 




19


ALPHA coating technology 

ALPHA coating technology is the culmination of Omega’s ongoing research and development regarding filter design and 

deposition techniques. Employing a proprietary method of controlling the coating process, this technology yields filters with 

exceptionally high signal-to-noise, as well as, steep transition slopes suitable for the most demanding applications. With ALPHA 

coating technology , optical systems achieve the highest level of spectral discrimination – images are brighter, contrast is 

enhanced and instruments perform to the limits of detection. Whenever an optical design demands the utmost level of precision, 

ALPHA coating technology is the obvious choice. 

Features/Benefits/Critical Specifications: 

• Extremely sharp transitions from stopband to passband 

• Precise, repeatable location of cut-on/cut-off wavelengths, tolerances 

within +/-0.01 to +/-0.005 of the edge 0.3OD - wavelength (50%) 

• Transmission 85% avg., 80% minimum, up to 8% gain with anti-reflection coatings 

• Tightly controlled ripple at cut-on 

• Nearly uniform transmittance across the passband 

• Exceptional attenuation of out-of-band signal 

• Single surface coatings suitable for PMT and silicon detectors 

• Optical quality transmitted wavefront 

• Longpass, shortpass and bandpass spectral profiles 

20 




Filter design 

All boundaries between media are divided into reflected and transmitted portions of the electromagnetic 

wave. Those portions of the wave not reflected are transmitted across the boundary to a new medium with dissimilar optical 

properties. These differences cause refraction, or a change in the speed and angle of the wave. A material’s refractive index is 

defined as the ratio of the velocity of light in a vacuum to the velocity of light in that medium. The amount of light reflected is 

related to the difference between the refractive indices of the media on either side of the boundary; greater differences create 

greater reflectivity. For non-absorbing media, if there is an increase in refractive index across the boundary, the reflected wave 

undergoes a phase change of 180º. If there is a decrease no phase change would occur. An optical thin-film coating is a stack 

of such boundaries, each producing reflected and transmitted components that are subsequently reflected and transmitted 

at other boundaries. If each of these boundaries is located at a precise distance from the other, the reflected and transmitted 

components are enhanced by interference. 

Unlike “solid” particles, two or more electromagnetic waves can 

occupy the same space. When occupying the same space, they interfere 

with each other in a manner determined by their difference 

in phase and amplitude. Consider what happens when two waves 

of equal wavelength interfere: when two such waves are exactly out 

of phase with each other, by 180°, they interfere destructively. If 

their amplitudes are equal, they cancel each other by producing a 

wave of zero amplitude. When two such waves are exactly in phase 

with each other, they interfere constructively, producing a wave of 

amplitude equal to the sum of the two constituent waves. 

An optical thin-film coating is designed so that the distances 

between the boundaries will control the phase differences of the 

multiple reflected and transmitted components. 

c) The polarization effects at non-normal angles of incidence. 

These characteristics are influenced by the number of boundaries, 

the difference in refractive index across each boundary and 

the various distances between the boundaries within a coating. 

When light does not strike an interference filter at normal (normal 

is orthogonal to the plane of the filter), the situation becomes a bit 

more complicated. We now must consider the transmission and 

reflection of light depending on the orientation of the electric field 

to the plane of incidence. This orientation of the light’s electric field 

to the plane of incidence is called the polarization of the light. The 

polarization of incident light can be separated into two perpendicular 

components called “s” and “p”. For a complete treatment of 

the behavior of light of different polarization, we recommend the 

classic textbook “Optics” by Eugene Hecht. For now, we’ll present 

Fresnel equations that describe the behavior of the two polarizations 

of light when they interact with a surface. 

The diagram below shows the relevant rays to our discussion. We’ll 

keep the notation used in the diagram for the Fresnel equations 

below: θ i 

is the angle of incidence, θ r 

is the angle of reflection and 

θ t 

is the refracted angle of transmission. 

Source: Thin Film Optical Filters by Angus Macleod 

When this “stack of boundaries” is placed in a light path, constructive 

interference is induced at some selected wavelengths, while 

destructive interference is induced at others. 

With the aid of thin-film design software, we apply optical thin-film 

theory to optimize various coating performance characteristics 

such as: 

a) The degree of transmission and reflection 

b) The size of the spectral range over which transmission, reflection 

and the transition between them occur 

First, we can use Snell’s Law to determine θ t 

from θ i 

: 

To find the amount of transmitted and reflected light, we use the 

Fresnel equations: 




21

filter design 

With most of our coatings, absorption is negligible, so transmittance 

can be found by: 

1-R = T. 

The following graph shows how the s and p portions of reflectance 

change as a function of angle of incidence for an air / glass interface: 

indistinguishable spectral function. Furthermore, the precise monitor 

of dense films make designs of extreme phase thickness a 

straight-forward process, and the resulting transmission within a 

small fraction of a percent from theoretical. 

Additional deposition chambers include the Leybold SYRUSPro 

1510. With 1.5 meters in possible capacity using a LION source for 

assisted condensation, these chambers provide both complexity 

and precision in a single system. 

These high capacity systems identify Omega Optical as not only the 

ideal supplier to the labs and research communities, but allow for 

unlimited production of resulting product developments. 

Complementing the energetic process systems are nearly thirty 

Physical Vapor Deposition (PVD) systems relying on evaporation by 

resistance or electron beam heating. 

THE COATING PROCESS 

We select coating materials for their refractive and absorptive characteristics 

at those wavelengths critical to the optical filters application. 

The coating process requires that materials be selected for 

their evaporation and condensation properties as well as for their 

environmental durability. 

Our Range of Deposition Chambers includes energetic 

process systems that rely on sputtering to release the solid to its gas 

phase (manufactured by Leybold Optics: www.leybold-optics.com). 

Subsequent to release from the solid, the deposition materials are 

converted from metal to dielectric in a plasma reaction. These 

reacted dielectric molecules are then densified in a high power 

ionic bombardment chamber. This process is repeated in a few 

milliseconds, so layers are deposited with virtually no defects, and 

with extreme precision. These Leybold Helios systems are claimed 

to be the most deterministic in the industry. 

Our close work with Leybold Optics has led to enhancements and 

improvements in the resulting coatings. Additional controls have 

been added to better define the uniformity of the deposition by both 

physical and magnetic confinements. Other features have been developed 

to allow a variety of materials, and precise direct control at 

nearly any wavelength of light. 

With large sputtering targets, and a 1 to 2 meter diameter platen, 

these deposition chambers have capacity that is unsurpassed. The 

combination of a vast coating region and extremely precise layer 

control results in the capability to produce any quantity with nearly 

Physical Vapor Deposition Coatings are produced in vacuum 

chambers at pressure typically less than 10-5 torr. The coating 

materials are vaporized by a resistive heating source, sputter gun 

(accelerated Ar ions) or an electron beam. With careful control of 

conditions such as vaporization rate, pressure, temperature and 

chamber geometry, the vapor cloud condenses uniformly onto 

substrates, then returning to their solid state. As a layer of material 

is deposited, its increasing thickness is typically monitored optically. 

For example, when zinc sulfide is deposited onto bare glass, the 

transmission will fall as zinc sulfide builds a layer on the glass. 

Based on the magnitude of this transmittance level, the precise 

thickness of the zinc sulfide layer is known. Once the transmittance 

falls to the point corresponding with the desired layer thickness, the 

chamber shutter is closed to prevent further deposition of the zinc 

sulfide. At this point, a second material will typically be added and 

monitored in a similar fashion. A multi-layer coating is produced 

by alternating this cycle (typically 20 to 70 times) with two or more 

materials. 

Successful production of a thin film interference filter relies on accurate 

and precise deposition of the thin film layers. There are a few 

different methods available to monitor the thickness of deposited 

layers. The two most commonly employed at Omega are crystal monitors 

and optical monitors and can be either automated or manual. 

Crystal Monitoring Small Crystals (usually quartz) have 

a natural resonant frequency of vibration. The crystal monitor is 

placed in the deposition cloud so that the crystal and substrate see 

directly proportional amounts of deposition regardless of deposition 

rate, temperature or other factors. As material deposits on the 

crystal, the vibration of the crystal slows down just like adding mass 

to an oscillating spring lowers the frequency of oscillation of the 

spring. Armed with the knowledge of the density of the material 

we are depositing, we can determine the thickness of the layer 

deposited. 

22 




With Optical Monitoring, the intensity of a single color of 

light passing through the substrate is continually monitored. 

As the thickness of a layer increases, the transmission of the 

substrate will change predictably. Even with many tens of layers, 

the transmission and reflection off a thin film stack is predictable 

and easily calculable with the benefit of a computer. While we 

usually optically monitor using transmitted light, it is also possible 

to optically monitor with reflected light 

Several of our deposition chambers have been outfitted for automated 

manufacturing. The use of a custom written application 

in “LabView” tells us when to precisely cut layers at the optimal 

thickness; using optical monitoring of real-time signal. 

For optimization of transmission and reflection regions, we employ 

a number of proprietary commercial packages. These tools 

allow for the best compromise in performance at all wavelengths 

in question. 

The Quarter-Wave Stack Reflector is a basic building block 

of optical thin-film products. It is composed of alternating layers of 

two dielectric materials in which each layer has an optical thickness 

corresponding to one-quarter of the principal wavelength. This 

coating has the highest reflection at the principal wavelength, and 

transmits at wavelengths both higher and lower than the principal 

wavelength. At the principal wavelength, constructive interference 

of the multiple reflected rays maximizes the overall reflection of 

the coating; destructive interference among the transmitted rays 

minimizes the overall transmission. 

Figure 1 illustrates the spectral performance of a quarter-wave 

stack reflector. Designed for maximum reflection of 550nm light 

waves, each layer has an optical thickness corresponding to one 

quarter of 550nm. This coating is useful for two types of filters: 

edge filters and rejection band filters. 

% Transmission 

100 

50 

0 

400 500 600 700 800 900 


Figure 1 

Quarter-Wave Stack 

Reflector 

The Fabry-Perot Interferometer, or a single-cavity coating, is formed 

by separating two thin-film reflectors with a thin-film spacer. 

In an all-dielectric cavity, the thin-film reflectors are quarter-wave 

stack reflectors made of dielectric materials. 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

825 830 835 840 845 850 855 

Figure 2 Single-Cavity Coating 


The spacer, which is a single layer of dielectric material having an 

optical thickness corresponding to an integral-half of the principal 

wavelength, induces transmission rather than reflection at the principal 

wavelength. Light with wavelengths longer or shorter than the 

principal wavelength will undergo a phase condition that maximizes 

reflectivity and minimizes transmission. The result is a passband 

filter. The size of the passband region, the degree of transmission 

in that region, and the degree of reflection outside that region is 

determined by the number and arrangement of layers. A narrow 

passband region is created by increasing the reflection of the quarter-wave 

stacks as well as increasing the thickness of the thin-film 

spacer. In a metal-dielectric-metal (MDM) cavity, the reflectors of 

the solid Fabry-Perot interferometer are thin-films of metal and the 

spacer is a layer of dielectric material with an integral half-wave 

thickness. These are commonly used to filter UV light that would 

be absorbed by all-dielectric coatings. 

The Multi-Cavity Passband Coating is made by coupling two 

or more single-cavities with a matching layer. The transmission at 

any given wavelength in and near the band is roughly the product 

of the transmission of the individual cavities. Therefore, as the 

number of cavities increases, the cut-off edges become steeper 

and the degree of reflection becomes greater. 

When this type of coating is made of all-dielectric materials, out-ofband 

reflection characteristically ranges from about (.8 x CWL) to 

(1.2 x CWL). If thin films of metal, such as silver, are substituted for 

some of the dielectric layers, the metal’s reflection and absorption 

properties extend the range of attenuation far into the IR. These 

properties cause loss in the transmission efficiency of the band. 

As mentioned previously, the choice of materials to be used in a 

multilayer design is very wide, ranging from metals to the oxides 

of metals, to the salts and more complex compounds, to the 

small molecule organics. General features required to be practical 

include environmental stability, stress, deposition, temperature, 

transparency, etc. Most of the industry limits the selection to refrac- 




23

filter design 

tory oxides. We have experience with a much wider selection. With 

our wide range of potential materials, coatings of many varieties are 

possible. We like to use the expression “there is no end in light.” By 

this, we mean we will attempt to satisfy any spectral function as one 

we can produce, until we have proven otherwise. 

List of coating materials: 

niobium (V) oxide - Nb 2 

O 5 

germanium - Ge 

magnesium fluoride - MgF 2 

tantalum (V) oxide - Ta 2 

O 5 

hafnium (IV) oxide - HfO 2 

zirconium (IV) oxide - ZrO 2 

aluminum oxide - AI 2 

O 3 

titanium (IV) oxide – TiO 2 


100 

90 

50 

45 

0 

T peak = 90% 

T peak = 45% 

2 

Figure 3 Multi-Cavity Passband Coating 

571.3 

zinc sulfide - ZnS 

cryolite - Na 3 

AIF 6 

aluminum - AI 

yttrium (III) fluoride - YF 3 

silver - Ag 

nickel chromium alloy - Inconel 

silicon dioxide - SiO 2 

gold - Au 

Figure 3 illustrates the spectral performance of a 3-cavity bandpass 

filter. Three features used to identify bandpass filters are center 

wavelength (CWL), full width at half maximum transmission 

(FWHM), which characterizes the width of the passband, and peak 

transmission (%T). 

Anti-Reflective Coatings do the opposite of a reflector. At 

the principal wavelength, it creates destructive interference for 

the multiple reflected waves, and constructive interference for the 

multiple transmitted waves. This type of coating is commonly applied 

to the surfaces of optical components such as lenses, mirrors, and 

windows. When deposited on the surface of an interference filter, 

the anti-reflective coating increases net transmission and reduces 

the intensity of ghost images. It should be noted that a properly 

designed longpass or shortpass filter is anti-reflective by nature at 

the relevant wavelengths and doesn’t need a second, additional 

anti-reflective coating. 

See Application Note: Types of Anti-Reflective Treatments and 

When to Use Them on page 29 

576.1 

CWL 

1 2 

FWHM 

550 560 570 580 590 600 


580.9 

A Partial Reflector, when manufactured from all dielectric 

materials, is similar to the quarter-wave stack reflector except 

that fewer layers are employed so that the reflectance is less 

than complete. Since virtually none of the light is absorbed the 

portion not transmitted is reflected. Partial beamsplitters often use 

this partial reflector stack. Here are a couple examples: A 50/50 

beamsplitter will reflect 50% and transmit 50% of the incident light 

over a given spectral range. A 60/40 will reflect 60% and transmit 

40%. 

Dielectric/Metal Partial Reflector and Neutral Density 

Metal Filters are two additional types of partial reflectors we 

offer. The dielectric/metal partial reflector is manufactured with a 

combination of metal and dielectric materials and absorbs some 

portion of the incident light. A neutral density filter, coated with the 

metal alloy “inconel” is a common metal partial reflector. 

Front Surface Coatings are employed when light must interact 

with the coating before passing through the substrate. Reflective 

surface coatings eliminate multiple reflections in products such as 

mirrors and dichroic beamsplitters. They also reduce the amount of 

energy absorbed by the substrate in some products. Anti-reflective 

coatings that reduce the degree of difference in admittance at the 

boundary of a filter and its medium are effective on both the front 

and back surfaces of a filter. 

Refractive oxides, fluorides and metals are surface coating materials 

chosen for their durability. Many optical components are 

protected by durable surface coatings. Common surface coatings 

have undergone testing that simulates many years of environmental 

stress with no observable signs of cosmetic deterioration and 

only minimal shift in spectral performance. Metal coatings are often 

over-coated with a layer of oxide or fluoride material to enhance 

their durability. 

Refractive oxide surface coatings are inherently unstable. The 

reactive coating process for oxides is critically dependent on deposition 

parameters. Methods such as ion beam sputtering and 

plasma coating have been developed to improve coating stability 

through energetic bombardment to produce a more dense coating. 

Surface coatings are typically more expensive than dielectric 

coatings due to lengthy manufacturing cycles, but provide extreme 

durability, excellent transmitted wavefront characteristics and can 

survive high temperature applications. 

Dielectric coatings may be protected by a cover glass laminated 

with optical grade cement. This allows use of materials which have 

wide ranging indices of refraction that result in increasing spectral 

control at a reasonable cost. A glass-to-glass lamination around the 

perimeter of the assembly provides moisture protection. 

The dielectric materials used to produce these coatings yield the 

24 




highest spectral performance. Research has shown that, although 

more fragile than refractive oxides, a single pair of dielectric materials 

permits the most complicated and highest performing interference 

designs. The benefits of this material include deep out-ofband 

blocking, very high phase thickness coatings with low residual 

stress, minimal crazing and substrate deformation, consistent and 

stable spectral performance, and simplicity of deposition which 

results in affordable cost. 

Extended Attenuation it is often necessary when using a light 

source or a detector that performs over a broad spectral range to 

extend the range of attenuation provided by a single-coated surface. 

Additionally, an increased level of attenuation might be necessary 

if a high-intensity source or a very sensitive detector is used. While 

some optical systems may be able to provide space for separate 

reflectors or absorbers, these attenuating components can often be 

combined with the principal coating in a single assembly. 

Adding attenuating components always results in some loss in 

transmission at the desired wavelengths. Therefore, optical density 

blocking strategies are devised for an optimum balance of transmission 

and attenuation. For example, if a detector has no sensitivity 

beyond 1000 nm, the filter’s optical density blocking is designed 

only to that limit, conserving a critical portion of the throughput. 

Extended attenuation sometimes is achieved by selecting thin film 

coating materials that absorb the unwanted wavelengths but transmit 

the desired wavelengths. Absorptive color glasses are commonly 

used as coating substrates or included in filter assemblies for 

extended attenuation. Dyes can also be added to optical cement 

to provide absorption. The choices of absorbing media are many, 

yet all face their own set of unique limitations. Absorbing media 

are 

100 

ideal for some blocking requirements such as the “short wavelength 

side” of a visible bandpass filter. However, these materials 

don’t provide the best levels of transmission, levels of absorption, 

or transition slopes in all situations. Furthermore, the temperature 

50 

increase caused by absorption can be great enough to cause significant 

wavelength shift or material damage. 

Dielectric thin-film coatings, either longpass or shortpass or very 

0 

wide bandpass, are also commonly used to extend attenuation 

400 450 500 550 600 650 700 750 800 850 900 

throughout the required spectral Wavelength region. (nm) Deposited onto substrates 

% Transmission % Transmission 

100 

50 

0 

Assembled 

Bandpass 

filter 

Interference 

coated blocking 

element #1 

400 450 500 550 600 650 700 750 800 850 900 


Figure 4 Bandpass With Extended Attenuation 

Longpass 

absorption 

glass 

Interference 

coated blocking 

element #2 

they are highly transmissive in the desired spectral region and highly 

reflective where the principal coating “leaks” unwanted wavelengths. 

Figures 4 illustrate how several blocking components increase the 

attenuation of a principal filter component. 

Metal thin-film bandpass coatings extend attenuation to the far IR 

(>100 microns). This approach is simpler than the all dielectric 

method in that a single component attenuates a greater range. 

Metal layers are absorptive however and can reduce transmission 

at desired wavelengths to levels between 10% and 60%. A comparable 

all dielectric filter, blocked to the desired wavelength, would 

allow transmission to 95% in theory, in practice would fall short and 

not achieve the necessary attenuation range. 

Our two most common strategies for extending the attenuation of 

a single coated surface are referred to as “optimized blocking,” for 

filters used with detectors sensitive only in a limited region, and 

“complete blocking” for filters used with detectors sensitive to all 

wavelengths. An optimized blocked filter combines a color absorption 

glass for the short wavelength side of the passband with a 

dielectric reflector for the long wavelength side of the passband. A 

completely blocked filter includes a metal thin-film bandpass coating, 

which is often combined with a color absorption glass to boost 

short-wavelength attenuation. 

Signal-to-Noise (S/N) ratio is often the most important 

consideration in designing an optical system. It is determined by: 

S/N = S / (N1 + N2 + N3) where: 

S = desired energy reaching the detector 

N1 = unwanted energy transmitted by the filter 

N2 = other light energy reaching the detector 

N3 = other undesired energy affecting the output (e.g., detector 

and amplifier noise) 

The optimum interference filter is one that reduces unwanted 

transmitted energy (N1) to a level below the external noise level 

(N2 and N3), while maintaining a signal level (S) well above the 

external noise. 

Filter Orientation in most applications is with the most 

reflective, metallic looking surface toward the light source. The 

opposite surface is typically distinguished by it’s more colored 

or opaque appearance. When oriented in this way, the thermal 

stress on the filter assembly is minimized. Spectral performance 

is unaffected by filter orientation. When significant, our filters are 

labeled with an arrow on the edge, indicating the direction of the 

light path. Special markings are made for those customers who 

require consistency with instrument design. 




25

filter design 

Excessive Light Energy can destroy a filter by degrading the 

coating or by fracturing the glass. Heat-induced glass damage can 

be avoided by proper substrate selection and by ensuring that 

the filter is mounted in a heat conducting sink. Coating damage 

is more complicated and a coating’s specific damage threshold 

is dependent on a number of factors including coating type, 

wavelength of the incident energy, angle of incidence and pulse 

length. 

Due to the ability to dissipate heat, a surface oxide coating will be 

the most damage resistant. A protected dielectric coating will be 

the most susceptible to damage. Surface fluoride, surface metal, 

and protected metal coatings will fall between these two extremes. 

Extensive experience with laser applications guides the selection of 

substrate materials and coating design best suited to meet specific 

spectrophotometric and energy handling requirements. 

Angle of Incidence and Polarization are important 

considerations when designing a filter. Most interference coatings 

are designed to filter collimated light at a normal angle of incidence 

where the coated surface is perpendicular to the light path. 

However, interference coatings have certain unique properties that 

can be used effectively at off-normal angles of incidence. Dichroic 

beamsplitters and tunable bandpass filters are two common 

products that take advantage of these properties. 

The primary effect of an increase in the incident angle on an interference 

coating is a shift in spectral performance toward shorter 

wavelengths. In other words, the principal wavelength of all types of 

interference filters decreases as the angle of incidence increases. 

For example, in Figure 5 the 665LP longpass filter (50% T at 

665nm) becomes a 605LP filter at a 45° angle of incidence. 

Where: 

ϕ = angle of incidence 

λϕ = principal wavelength at angle of incidence φ 

λ 0 = principal wavelength at 0º angle of incidence 

N = effective refractive index of the coating 

The effective admittance of a coating is determined by the coating 

materials used and the sequence of thin-film layers in the coating, 

both of which are variables in the design process. For filters with 

common coating materials such as zinc sulfide and cryolite, effective 

refractive index values are typically 1.45 or 2.0, depending 

upon which material is used for the spacer layer. This relationship 

is plotted in Figure 6. The actual shifts will vary slightly from calculations 

based solely on the above equation (alternating SiO 2 

and 

Nb 2 

O 5 

have values of 1.52 and 2.35). 

A secondary effect of angle of incidence is polarization. At angles 

greater than 0º, the component of lightwaves vibrating parallel to 

the plane of incidence (P-plane) will be filtered differently than 

the component vibrating perpendicular to the plane of incidence 

(S-plane). The plane of incidence is geometrically defined by a 

line along the direction of lightwave propagation and an intersecting 

line perpendicular to the coating surface. Polarization effects 

increase as the angle of incidence increases. Figures 5 and 7 illustrate 

the effects of polarization on a longpass and a bandpass filter. 

Coating designs can minimize polarization effects when necessary. 

1.00 

0.98 

0.96 

N = 2.0 

100 

0.94 

CWL 

CWL 0 

0.92 

N = 1.45 


P-plane at 45º 

50 

0º incidence 

S-plane at 45º 

45º incidence 

unpolarized light 

0 

450 500 550 600 650 700 750 


0.90 

0.88 

0.86 

0 5 10 15 20 25 30 35 40 45 50 55 60 

Angle of Incidence (º) 

Figure 6 

Angle of Incidence Effects 

Figure 5 Angle of Incidence Polarization Effects – Longpass Filter 

The relationship between this shift and angle of incidence is described 

approximately as: 

System Speed can have a significant effect on transmission 

and bandwidth as well as shifting peak wavelength. Faster system 

speeds result in a loss in peak transmission, an increase in 

bandwidth and a blue-shift in peak wavelength. These effects can 

be drastic when narrow-band filters are used in fast systems, and 

need to be taken into consideration during system design. 

When filtering a converging rather than collimated beam of light, 

the spectrum results from the integration of the rays at all angles 

26 




exposure to light, particularly short UV wavelengths, results in solarization 

and reduced transmission. 

Figure 7 Angle of Incidence Polarization Effects – Bandpass Filters 

within the cone. At system speeds of f/2.5 and slower (full cone 

angle of 23° or less), the shift in peak wavelength can be approximately 

predicted from the filter’s performance in collimated light 

(i.e., the peak wavelength shifts about one-half the value that it 

would shift in collimated light at the cone’s most off-axis angle). 

Temperature Effects the performance of an interference 

filter. Wavelength will shift with temperature changes due 

to the expansion and contraction of the coating materials. 

Unless otherwise specified, filters are designed for an operating 

temperature of 20°C. They will withstand repeated thermal cycling 

assuming temperature transitions are less than 5°C per minute. 

An operating temperature range between -60°C and +60°C is 

recommended. For the refractory oxides temperature ranges from 

-60°C to 120°C. Filters must be specifically designed for use at 

temperatures above 120°C or below -100°C. Although the shift is 

dependent upon the design of the coating, coefficients in Figure 8 

provide a good approximation. 

For applications where the change in performance divided by the 

change in temperature is to be minimized, the densified refractory 

oxide materials are preferred. Consideration must be given to 

maximize temperature as refractory oxides, even when densified 

through energetic process, will experience a one-time shift in optical 

thickness. The magnitude of this is

filter design 

Transmitted Wavefront Distortion is measured at the filter’s 

principal wavelength on a Broadband Achromatic Twyman-Green 

Interferometer or a Shack-Hartmann interferometer. Although many 

interferometers can measure transmitted wavefront distortion, 

most are fixed at a single wavelength (often 633nm). For filters that 

don’t transmit this wavelength, these instruments must produce 

reflected, rather than transmitted, interferograms. 

Figure 9 

Transmitted wavefront 

interferogram of a narrow 

band filter used for 

telephotometry. 

Although reflected interferograms are often used to represent the 

quality of a transmitted image, there are no reliable means for such 

interpretation. 

See Application Note: Measuring Transmitted Wavefront 

Distortion on page 34 

Image Quality Filters: An optical filter’s effect on the quality 

of an image results from the degree it distorts the transmitted 

wavefront. 

In high-resolution imaging systems, filters require multiple layering 

of various materials (i.e., glasses, coating materials, optical 

cements, etc.) for high spectral performance. These materials, if 

used indiscriminately, can degrade a filter’s optical performance. 

This effect can be significantly diminished through material selection, 

design, process, and testing. 

To preserve image quality we select optical grade materials with 

the highest degree of homogeneity and the best match in refractive 

index at contacted boundaries. Special coating designs minimize 

the required number of contacted surfaces that cause internal 

reflection and fringe patterns. Before coating and assembly, all 

glasses are polished to requisite flatness and wedge specifications. 

Our coating and assembly techniques assure uniformity in material 

as well as spectral properties. With sputtering and other energetic 

process coatings, very high optical quality can be maintained on 

monolithic surfaces of fused silica. Multiple substrates of this type 

may also be assembled to produce a desired spectrum function. 

After the filter is assembled, transmitted wavefront distortion can 

be improved further through a cycle of polishing, evaluating and 

re-polishing both outer surfaces. Durable anti-reflective coatings 

are then deposited onto the outer surfaces, reducing the intensity 

of ghost images while boosting transmission. See Figure 9. The 

resulting level of performance depends on size, thickness, spectral 

region and spectral demands of each filter. This approach has 

been used for filters of the highest standard such as the Space 

Telescope. 

28 




Types of Anti-Reflective 

Treatments and When to Use Them 

Application Note 

While no single solution fits all needs, by appropriately selecting the right anti-reflective technique, nearly any optic can be antireflected 

to meet the needs of the user. 

– by Dr. Michael Fink, Project Scientist, Omega Optical 

From the benign annoyance of a reflection off your car’s instrument 

panel window to the image-destroying reflections off of multiple 

optical components in a microscope, unwanted reflections plague 

our lives. Minimizing reflections has become a multimillion dollar 

industry. Scientific instruments with several optical components, 

such as modern confocal microscopes and, more commonly, television 

cameras, would be far less useful without the benefit of 

anti-reflective coatings. 

Discovery 

More than 70 years have passed since the first anti-reflective coating 

was discovered by a Ukrainian scientist working for Zeiss in Germany. 

While the anti-reflective coating was first implemented on binoculars 

in the German military, the new finding quickly expanded to a 

wide variety of optical elements in the research laboratory. 

On Reflections 

First, it is probably worthwhile to consider why reflections occur. 

Reflection of light occurs at any surface between two mediums with 

different indices of refraction. The closer the two indices of refraction, 

the less light will be reflected. If an optic could be made out of 

a material with the same index of refraction as air, then there would 

be no reflections at all. Of course, lenses would not focus light if 

they didn’t have an index of refraction that differed from that of air 

(or whatever medium they’re immersed in). 

Figure 1 Percent reflectance of s and p-polarized light off silicon and fused 

silica surfaces depending on angle of incidence. 

( n 

Si = 4.01, n 

fused silica = 1.46). 

In general, the reflection of light off of a surface will increase as 

the angle of incidence varies further from normal. However, this is 

not true for light that is p-polarized. Reflection of p-polarized light 

will decrease as the angle of incidence increases from normal (0°) 

to some angle at which there is no reflection. This angle at which 

there is no reflection of p-polarized light is called Brewster’s angle 

and varies depending on the indices of refraction of the two media. 

For 1,064 nm light at an interface of air and fused silica, Brewster’s 

angle is approximately 55.4°. Brewster’s angle is different depending 

on the two media that comprise the interface. Figure 1 compares 

the reflection of s- and p-polarized light for air-fused silica 

and air-silicon surfaces. At angles of incidence greater than Brewster’s 

angle, the reflection of both s- and p-polarized light increases 

dramatically as the angle of incidence increases. 

Uses and Misuses 

of Anti-Reflective Treatments 

Often, anti-reflective coatings are used to increase transmission of 

an optic. This is often a valid use of an anti-reflective coating, but it 

should be noted that this coating does not, by definition, increase 

transmission. Rather, it only reduces reflections off the incident side 

of the surface. In some cases, absorptive anti-reflective treatments 

can actually reduce transmission. In the case of interference filters, 

an anti-reflective treatment is often superfluous. An interference filter 

is intentionally reflective at wavelengths that are not being passed, 

so the total reflection off the optic will not be effectively reduced by 

an anti-reflective treatment. Furthermore, exposed interference filters 

are often already anti-reflected at the passed wavelengths, so an 

extra anti-reflective coating usually has little effect. 

In many cases, the enhanced transmission of some anti-reflective 

coatings is very necessary. In fact, the advent of anti-reflective optics 

has made new optical instruments containing many-element apparatuses 

feasible. For example, a modern confocal microscope might 

have 15 or 20 optical elements in the light path. Borosilicate glass 

that has not been treated to eliminate reflections typically has a reflectance 

of about 4% in visible wavelengths per surface. A piece 

of borosilicate glass with a simple multilayer anti-reflective coating 

might average 0.7% reflectance per surface. When a single interface 

is concerned, the difference between 96% transmission and 

99.3% transmission seems miniscule. However, in a multi element 

light path, this difference becomes very significant. If an incident 

light path crosses 30 air-glass surfaces, the final transmitted light at 

the end of the path would only be approximately 29% for non-antireflection 

treated optics. An identical path with anti-reflection treated 

parts would be 81%. 




29

application note Types of Anti-Reflective Treatments and When to Use Them 

Anti-Reflective Coatings 

The predominant method for causing anti-reflection of an optic is 

by depositing a layer or several layers of compounds onto the surface 

of the optic. Deposited anti-reflective coatings vary in complexity 

from single layer to 10 or more layers. Popular deposition 

methods of chemical anti-reflective coatings include sputtering, 

chemical vapor deposition, and spin-coating. 

Single-Layer Anti-Reflection 

Single-layer anti-reflective coatings are the simplest and often the 

most sensible solution. With just a single layer of a well-chosen 

compound, reflection at a specific wavelength can be reduced 

almost to zero. Additionally, unlike multilayer coatings, there is no 

wavelength or angle of incidence at which the reflection is greater 

than is reflected off an untreated substrate. 1 

While the “perfect” compound to make an anti-reflective coating 

for visible wavelengths does not yet exist, single layer anti-reflective 

coatings still are often implemented in this range. 

To anti-reflect a specific wavelength with one layer of coating, ideally 

a compound would be used that has an index of refraction that 

is midway between the indices for air and the optical substrate. Additionally, 

the optical thickness of the anti-reflective layer is usually 

chosen to be one-quarter wave. If both of these criteria can be 

met, the theoretical reflection at that specific wavelength is zero. 

There are practical considerations that prohibit this in the visible 

wavelengths. 

Most glasses used in the optical laboratory today have indices of 

refraction between 1.4 and 1.6. These values would suggest an 

optimal anti-reflective coating index of refraction between 1.20 and 

1.30. Unfortunately, there are no known suitable compounds that 

have an appropriate index of refraction, are suitably durable, and 

can withstand the typical laboratory environment. 

One compound that is commonly used for single layer anti-reflective 

coatings for visible spectrum elements is magnesium fluoride 

(MgF2). It has an index of refraction that is close to optimal 

(~1.38 at 500 nm) and is easily deposited onto glass. With carefully 

controlled process and substrate temperatures of 200° C to 250° 

C, a very robust coating can be applied, but otherwise care must 

be taken while cleaning magnesium fluoride-coated surfaces, as 

the coating can be rubbed off with vigorous cleaning. A theoretical 

reflectance curve for a single layer of MgF2 is shown in figure 2. 

The reflection gains at off-normal angles of incidence are relatively 

small for single-layer coatings, as shown in figure 3. 

Single-layer anti-reflective coatings are especially popular when 

anti-reflection in the infrared is desired. Because many of the substrates 

used in infrared have higher indices of refraction (i.e., silicon, 

germanium, gallium arsenide, indium arsenide), there are many 

more choices for an optimal anti-reflective coating compound than 

for glasses. For example, the above-mentioned infrared substrates 

all have indices of refraction close to 4. A single layer of zinc sulfide 

can be used to anti-reflect all of these substrates quite effectively. 2 

V-Coating (Two-Layer Anti-Reflection) 

If very low reflection is needed, but at only one specific wavelength, 

v-coating, a two-layer anti-reflective coating, is often the best solution. 

By using two layers with contrasting indices of refraction, 

it is possible to reduce the reflection at a specific wavelength to 

near zero. A drawback of this technique is that it actually increases 

reflection at wavelengths other than that for which the coating is 

optimized (evident on figure 2). If the actual goal is to minimize 

reflections at multiple wavelengths, v-coating will not produce the 

desired result. 

Figure 2 Theoretical reflectance curves for untreated borosilicate float 

glass and borosilicate float glass with three different anti-reflective 

coatings. 

Figure 3 

Reflectance off borosilicate glass 

surface treated with a single layer of 

MgF2. The reflectance is not as low 

as a multi-layer BBAR coating, but 

it is lower than untreated glass at all 

wavelengths and incident angles. 

Multilayer Coatings 

For broadband anti-reflection of less than 1% in the visible wavelengths, 

multilayer coatings are required. Broadband anti-reflective 

(BBAR) coatings have an advantage of producing very low 

reflection over a controllable, broad range of wavelengths (figure 

2). Beyond the region for which the coating is optimized, such as 

the v-coating, reflection off the optic is greater than reflection from 

untreated glass. BBAR coatings suffer slightly larger percentage 

reflection gains at off-normal angles of incidence when compared 

with single-layer anti-reflective coatings. Figure 4 illustrates these 

large reflectance gains at off-normal angles of incidence for multilayer 

coatings. 

30 




Figure 4 Multi-layer broadband anti-reflective (BBAR) coatings can achieve 

reflections below 1% at a broad range of wavelengths, but at the 

expense of higher out-of-band reflectance and large percentage 

gains in reflectance at non-normal angles of incidence. 

Materials 

Anti-reflection in the visible and near-IR wavelengths can be achieved 

with a variety of different deposited compounds. Silicon monoxide, 

yttrium fluoride, and magnesium fluoride are three popular 

low-index-of-refraction materials. Silicon monoxide is used primarily 

in the infrared wavelengths, while yttrium fluoride and magnesium 

fluoride are used most frequently in the visible region. The 

primary drawback of these compounds is their durability. While 

anti-reflective coatings utilizing either of these can be cleaned, 

care must be taken not to cause damage. Anti-reflective coatings 

also can be made using harder oxide compounds that are more 

durable, but they tend not to perform quite as well and require that 

the optic be subjected to high temperatures during deposition. In 

general, the more energetic (higher temperature) the process that 

is used to deposit the anti-reflective coating, the more durable the 

resultant coating is. 

Moth-Eye and Random 

Microstructured Anti-Reflection 

The physical structure of moths’ eyes gives these insects a unique 

means of minimizing reflection. Reduced reflections off of moths’ 

eyes can make the difference between their being eaten by a 

predator or remaining unseen. As a result of this environmental 

pressure, moths have evolved a regular repeating pattern of 3-D 

prominences on the surface of their eyes that effectively reduce 

reflection. With some effort, scientists have been able to duplicate 

the “moth-eye” pattern on glass to achieve a similar anti-reflection 

effect. 

Initially, it seems non-intuitive that simply changing the surface 

structure of the glass should reduce reflections off that surface. By 

changing the initially smooth, flat surface of the glass to a surface 

that has a regular pattern of prominences that are hundreds of 

nanometers in size, the surface area has actually increased dramatically. 

Increased surface area would seem to suggest higher 

reflection rather than lower. 

The reason for the reduced reflection off of a moth-eye surface is 

that the light no longer has a distinct boundary between the air and 

glass (or air and eye of the moth). Where there once was a very 

sharp boundary between air and glass, the transition now occurs 

over an appreciable fraction of a wavelength. Because reflections 

only can occur where there is a change in index of refraction and 

there is no longer a sharp boundary between materials, reflections 

are drastically reduced. In the visible range on fused silica, motheye 

anti-reflection treatment can achieve broadband reflection off 

each surface of 0.2% or better. 

It is important to note that the size of the microstructures is very important. 

The structure on moths’ eyes is a regular repeating pattern 

of hexagonal finger-like projections that are spaced roughly 300 

nm from each other and rise about 200 nm from the eye’s surface. 

This size of microstructure is optimized roughly for anti-reflection 

of the visible spectrum. If the structures are made slightly smaller 

or larger in size, the surface can be optimized to reflect shorter or 

longer wavelengths, respectively. 

For example, arsenic triselenide is used in optics in the 5- to 

15-micron range. A typical moth-eye structure for this window of 

wavelengths might have prominences that rise 3,500 nm from the 

substrate surface with an average spacing between prominences 

of about 2,400 nm. 3 Moth-eye structures of approximately this size 

can be seen in figure 5. Typical transmission improvement of the 

optic can be as much as 12% to 14% by treating just one side of 

the optic (figure 6). 

One major advantage of microstructured antireflective glass is its 

ability to withstand high incident energies of nearly 60 J/cm. 4 

Figure 5 

SEM image 

of zinc selenide 

motheye 

microstructures. 

(Courtesy of 

TelAztec, Inc.) 




31

Types Of Anti-Reflective 

Treatments And When To Use Them 

application note Types of Anti-Reflective Treatments and When to Use Them 

This is a sizeable improvement over the energy damage threshold 

of most thin-film anti-reflective coatings. Because the antireflective 

“coating” is made of the glass itself, it will have an energy damage 

threshold similar to that of the glass from which the optic is made. 

To anti-reflect glass at visible wavelengths, an equally effective 

and more cost-effective anti-reflective coating can be created by 

etching the glass in a random pattern. An image of the resultant 

random spacing of the prominences is shown in figure 7. Treating 

a fused silica surface to create this random microstructure pattern 

can decrease broadband visible reflections by 80% to 90%. 

Cleaning of microstructured anti-reflective surfaces poses a small 

problem. Physical cleaning of microstructured surfaces must be 

done carefully, if at all. The prominences that give the substrate its 

anti-reflective property can be easily broken off if the cleaning is 

too vigorous. 

Absorptive Anti-Reflective Coatings 

Another method for minimizing reflections off an optic is to make 

the substrate more absorptive. If the goal is to improve transmission 

through the optic, use of an absorptive optical coating generally will 

not help. However, absorptive coatings can very effectively absorb 

light that would otherwise be reflected. 

Absorptive coatings are not usually the best solution for high-energy 

applications because, rather than transmitting the light that is 

being anti-reflected, that light now is being absorbed by molecules 

in the optical element, inevitably leading to heating and thermal 

damage. 

Summary 

Figure 7 

SEM image of 

random AR microstructures 

in 

glass. (Courtesy 

of TelAztec, Inc.) 

There are a few different options available for building an anti-reflective 

optic. While no single solution fits all needs, by appropriately 

selecting the right anti-reflective technique, nearly any optic 

now can be anti-reflected to meet the needs of the user. 

Dr. Michael Fink studied chemistry as an undergraduate at Bates 

College in Lewiston, ME, where he worked in the laboratory of 

Dr. Matthew Côté building a scanning tunneling microscope to 

determine the feasibility of using two color-distinguished oxidation 

states of tungsten oxide as a digital information storage medium. At the 

University of Oregon in Eugene, OR, Mike continued his studies, earning 

his doctorate in chemistry by improving the sensitivity of molecular 

Fourier imaging correlation spectroscopy in Dr. Andrew Marcus’s lab at 

the Oregon Center for Optics. 

References 

• 1. Johnson, Robert. AR coatings application note. 2006. 

• 2. Hass G. 1955. Filmed surfaces for reflecting optics. J. Opt. Soc. Am. 

45: 945-52. 

• 3. Hobbs, Douglas S., Bruce D. MacLeod & Juanita R. Riccobono. 

“Update on the Development of High Performance Anti-Reflecting 

Surface Relief Micro-Structures.” SPIE 6545-34. April 12, 2007. 

• 4. Ibid. 

Figure 6 Percent transmission for a ZnSe window untreated and treated with 

motheye AR texture on one side. (Courtesy of TelAztec, Inc.) 

32 




Filter Design Considerations 

and Your Light Source 


Overview 

Available to system designers today are a wide array of excitation sources. Among the most frequently used are semiconductor 

lasers, LEDs (light emitting diodes), arc lamps, gas and solid state lasers, gas discharge lamps, and filament lamps. Each of these 

excitation sources have distinct physical and spectral characteristics which make it an optimum choice for a particular application. 

In practically all cases however, regardless of which excitation source is selected, the use of a properly designed excitation filter is 

required to enhance system performance and optimize signal-to-noise ratio. 

While an excitation filters role is the same in every system, that is to deliver the desired excitation wavelengths while attenuating 

unwanted energy, the characteristics of the filter that achieve these goals are highly dependant on both the source characteristics 

and the overall system environment. 

– by Mark Ziter, Senior Applications Engineer, Omega Optical 

Filters for Gas and Solid State Lasers 

Traditionally, gas lasers have been popular excitation sources. 

The most common, Argon ion and Krypton ion, provide lines at 

488nm, 514nm, 568nm and 647nm. The laser emissions from 

these sources are precisely placed, exhibit narrow bandwidths, and 

are not subject to drift. While the output of such lasers are usually 

thought of as monochromatic, there are often lower energy transitions, 

spontaneous emissions, and plasma glow present in the 

output, all contributing to unwanted background. A filter to clean 

up the laser output and eliminate this noise will greatly enhance the 

system’s signal to noise ratio. 

Solid state lasers have properties similar to gas lasers. Along with the 

well behaved narrow primary laser emissions, these sources produce 

background noise from unwanted transitions and pump energy. 

Excitation interference filters for both gas and solid state lasers 

share similar design considerations. The narrow bandwidth and 

wavelength predictability of these lasers means that filters designed 

for these sources can have very narrow passband widths. Deep out 

of band blocking to attenuate the background is required to ensure 

that no unwanted excitation source error energy reaches the detector 

and deteriorates the signal-to-noise figure 

QuantaMAX Laser Line Filters (see page 57) are ideally suited 

to these applications. These filters, designated with an XLL prefix, 

have high transmission coupled with narrow pass bands, typically 

less than 0.4% of the laser wavelength. Manufactured with hard 

oxide surface coatings on monolithic high optical quality substrates, 

they exhibit exceptional thermal stability, shifting less than 

a few 1/100th of an Angstrom per deg C. The dense thin film coatings, 

deposited by energetic process, are unaffected by environmental 

humidity and their ability to withstand high power densities 

is unsurpassed in the marketplace. 

Filters for Diode Lasers 

The output of diode lasers is not as narrow or as precise as the output 

of gas and solid state lasers. These semiconductor devices have 

bandwidths in the 2nm to 5nm range. In addition, the actual output 

wavelength can vary a few nanometers from laser to laser. Compounding 

this lot to lot variation is the tendency these lasers have to drift 

with temperature and age. As a consequence, semiconductor lasers 

have an output wavelength uncertainty of up to +/- 5nm. Therefore, 

a diode laser designated as a 405nm device could have an output 

anywhere from 400nm to 410nm. Similarly, a 635nm diode laser 

may emit as blue as 630nm or as red as 640nm. 

Optical interference filters designed for semiconductor lasers must 

be wide enough to accommodate this uncertainty in output wavelength. 

Additionally, since a given diode laser will drift with temperature, 

any ripple in the filter’s spectral profile will result in an 

apparent variation in laser output intensity as the wavelength drifts 

across the filter passband. 

Both of these considerations have been taken into account in the design 

of our XLD (Laser Diode Clean-Up) Filters. See page 54. Similar to all 

QuantaMAX filters, these are manufactured using ion beam 

sputtering to produce stable, dense surface coatings on high optical 

quality substrates. With wider passbands than our Laser Line 

Filters, the XLD filters will transmit a designated diode laser’s output 

across its range of wavelength uncertainty. Their smooth transmission 

profiles, with less than +/- 1.5% transmission ripple across the 

passband, will not impart variation in laser intensity as the diode 

laser drifts with temperature. These filters’ deep out of band blocking 

will eliminate the secondary emissions that are typical with 

semiconductor lasers. 




33

application note Filter Design Considerations and Your Light Source 

Filters for LEDs 

Light emitting diodes, or LEDs, are semiconductor devices that 

emit light as a result of electron-hole recombination across a p-n 

junction. Due to the absence of stimulated emission and laser oscillation, 

the spectral output of a LED is much broader than that of 

a diode laser, typically 30nm to 50nm at the half power points. In 

addition, the lot to lot wavelength variation of a given LED can be as 

large as 20nm. Spectral profiles of LEDs show long emission tails 

with substantial energy that usually extends well into the signal region. 

Often, the energy in these tails is the same order of magnitude 

as the signal to be detected. 

Filters for LED excitation must attenuate the red tail. In order to allow 

signal collection as spectrally close as possible to the excitation, 

the filter needs a very steep blocking slope on its cut-off edge. Additionally, 

the filter needs to accommodate the wide LED bandwidth 

and output wavelength variability. Unless system requirements 

necessitate deep blocking at wavelengths blue of the LED output, 

there are few requirements on the blue cut-on edge. This edge 

can have a shallow blocking slope and does not need to be precisely 

placed. In fact, a short pass design is often the best choice 

to filter an LED excitation source. A steeply sloped short pass filter 

will eliminate the LED’s red tail and the open ended transmission 

to the blue will pass the wide, variable LED output. The simplicity 

of design and high transmission offered by a short pass approach 

makes this an attractive alternative. 

Filters for Hg Arc Lamps 

Arc lamps produce light by passing an electric current through 

vaporized material within a fused quartz tube. The mercury arc 

lamp is a very popular excitation source for fluorescence microscopy 

because its spectral content has a number of very strong 

prominences at useful wavelengths throughout the UV and visible 

regions. The most commonly used are at 365nm, 405nm, 436nm, 

546nm, and 579nm. Fluorescent dyes have been developed with 

absorption peaks that correspond with these emission lines. In order 

to take full advantage of these intense lines, we offer fluorescence 

microscopy sets with excitation filters designed specifically 

at these wavelengths. These include the XF408 (DAPI), the XF401 

(CFP), and the XF406 (mCherry) sets. 

Filters for Halogen Lamps 

A halogen lamp is a tungsten filament incandescent lamp with the 

filament enclosed in an environment consisting of a mixture of inert 

gas and a halogen, such as iodine. The presence of the halogen 

causes evaporated tungsten to be redeposited back onto the filament, 

extending the life of the bulb and allowing it to be operated 

at a high temperature. The halogen lamp spectral output is continuous 

from the near UV out to the IR. 

The continuous output spectrum of the halogen lamp removes all 

constraints on the wavelength placement and bandwidth of excitation 

filters designed to function with these sources. Where filters 

designed for all of the previously discussed sources need to be 

placed to take advantage of those sources spectral characteristics, 

no such considerations are required for filters designed to work 

with halogen lamps. The placement of cut-on and cut-off edges are 

determined solely by the absorption characteristics of the excited 

material and the spectral profile of the emission filter with which the 

excitation filter will function. 

The characteristic of the halogen lamp which affords this excitation 

filter design latitude also increases the filter’s blocking burden. The 

lack of prominences or bright lines means that the out of band 

energy levels to be blocked are of equal intensity to the desired 

wavelengths. Consequently, excitation filters for halogen lamps 

must block very deeply, especially red of the excitation band where 

the emission band is located. Also, since the Stokes shift of most 

fluorescence dyes dictates that the excitation and emission filter 

passbands be in close spectral proximity, a steep blocking slope on 

the red edge of the excitation pass band is required. A 5 decade 

slope of 1% or less is usually needed to prevent excitation energy 

from leaking into the emission range. For the same reason, the red 

edge spectral placement must be tightly toleranced. 

Whatever your light source might be, we are always available to 

assist in the selection of the right interference filters for the best 

performance. Please contact us. 

34 




Optical Interference Filters for 

Applications Using a LED Light Source 


Overview 

Light Emitting Diodes, or LEDs, are high efficiency sources of electro-magnetic energy with a wide range of available wavelengths 

and very high brightness. These devices directly convert electrons to photons, rather than producing photons through blackbody 

radiation as a consequence of electron conversion to heat. As a result, there is little associated thermal pollution, or wasted energy. 

LED Characteristics 

although very effective at producing luminous power for scientific 

applications, LEDs have an assortment of limitations that must be 

considered. The primary limitation is that although they are very 

bright in lumens per unit area, they are quite limited in absolute 

power. A related limitation results from the fact that as current is 

increased across the light producing junction, the temperature also 

increases, causing a thermal shift of output wavelength. Whether 

caused by a change in the temperature of the environment, or by 

the residual heat of driving the junction to produce more photons, 

the consequence is that the output wavelength drifts. 

Consistency limitations are exacerbated by the tendency of the 

output wavelength to vary from batch to batch. Minor variations 

in host impurities result in lot variations of Center Wavelength 

(CWL) of as much as 10nm, with occasional lots falling outside this 

range. Selection is a possible solution, but may result supply chain, 

inconsistencies. 

At low levels of output, LEDs exhibit bandwidth (FWHM or HBW) 

which is typically 30 nm. At greater power outputs, they produce 

coherent emission which has a distinctive spectral power function. 

The characteristic of this emission is a region of intense spikes 

of energy superimposed on the continuum. These spikes have 

bandwidths which are typically 1 nm and can occur in groups of 

up to ten bands within a region of 5nm of a central peak. 

Although much of the energy of LEDs is emitted in the specified 

region, there typically are secondary regions of light output. Usually 

these regions of secondary output are at significantly longer 

wavelengths, with infrared output at nominally twice the primary 

wavelength. 

Without filtering, the secondary spectral output of LEDs can 

reduce their effectiveness in devices designed for low level photon 

conversion, such as fluorescence or Raman scattering. Even if the 

secondary output is six orders of magnitude less than the primary, 

it would contribute a critical error in these applications, made 

even more serious by the enhanced IR sensitivity of silicon based 

detectors. 

Filter Recommendations 

When considering filters or filter sets suitable for LED light source, 

it is important to verify that the LED peak band is transmitted by the 

excitation filters and reflected by the dichroic mirror. This can be 

accomplished by a quick check of the filter’s spectral description 

to that of the LED’s center wavelength. 

For most commercial scientific grade LED sources it is probable 

that the standard filter sets used with a broad band lightsource, 

such as a Mercury burner, will suffice. 

When using a custom LED, or LED array, a customized optical filter 

solution may be acquired. 

Please contact us for assistance with filter selection. 

See Light Source Reference Charts on page 109 

“CoolLED recommends that excitation filters are used 

with its LED excitation products. Although LEDs produce 

a narrowband of excitation, there can be a small "tail" of 

excitation to shorter and longer wavelengths which may 

be undesirable for some applications.” 




35

Measuring Transmitted 

Wavefront Distortion 


Overview 

What is Transmitted Wavefront Distortion? If you’ve ever looked through an 

old piece of window glass and noticed the image on the other side is distorted, 

then you are familiar with the effects of transmitted wavefront distortion 

(TWD) (Figure 1). Transmitted wavefront distortion refers to the deformation of 

a plane wave of light as it travels through an optical element (Figure 2). 

Interference filters and dichroics for fluorescence and astronomy applications 

demand extraordinarily low levels of TWD. The acceptable TWD tolerance for 

these applications is often much tighter than can be perceived with the naked 

eye. When tight tolerances for TWD are required specialized instrument devices 

are necessary. This article focuses on one such device used by Omega 

Optical to measure TWD: the Shack-Hartmann wavefront sensor.. 

– Dr. Michael Fink, Project Scientist, Omega Optical 

Figure 1 

The effect of severe wavefront distortion is visible in this 

photo taken through a piece of cookware glass. 

Methods for Quantifying Transmitted Wavefront Distortion 

Interferometric Method 

The primary alternative to the Shack-Hartmann detector is 

interferometry. An interferometric measurement of TWD works by 

interfering two plane waves. If the plane waves have traveled the 

same path length and are parallel, the resulting interferogram of 

the plane waves should be a field with uniform intensity. If we insert 

an imperfect optic into one of the two interferometer light paths, the 

optical path length is no longer constant for all parts of the wave. 

Some parts of the wave will be deflected or phase-shifted more 

than others due to imperfections of the optic. As a result, when 

light from the two light paths is recombined, the resulting pattern 

will no longer be uniform. Places where light destructively interferes 

will be dark and places where the light constructively interferes 

will appear bright. Some commonly resulting patterns can be seen 

below in figure 3. 

Figure 2 

A plane wave travels through a slightly imperfect piece of glass. The 

resulting plane wave (red) deviates slightly from the original plane wave 

(black – shown as if it had not passed through any optic.) 

Figure 3 

Depiction of interferograms a) Relatively uniformly intense field 

created by two parallel, plane waves, b) parallel fringes created 

by plane waves that are not parallel, c) curved fringes created 

by interfering a plane wave (reference leg of the interferometer) 

and a plane wave that has been distorted by an intervening optic. 

Specialized software is used to translate the fringe pattern into a 

quantitative value of TWD. 

36 




Shack-Hartmann Method 

“Shack-Hartmann” derives from the names of two researchers who 

were responsible for advancing one of the primary components of 

the sensor, the lenslet array. The idea of creating an array of light 

points by spatial screening was first implemented by Johannes 

Hartmann in Germany in 1900 . Seventy-one years later, Roland 

Shack published a paper describing how the screen could be 

improved by replacing the apertures with tiny lenses . Shack’s 

lenslet array was implemented for the purpose of measuring TWD. 

A Shack-Hartmann instrument employs a completely different 

method for measuring TWD. The following diagram displays a 

simple Shack-Hartmann setup. 

Light focused on the camera sensor of a Shack-Hartmann detector 

will change position depending on the wavefront of the incoming 

light. In the top scenario, the light is a perfect plane wave and 

each microlens focuses the light to a point right in the center of 

its own region of the camera sensor. In the bottom scenario, the 

wavefront is distorted and the spots are no longer focused in the 

region directly behind the microlens. Instead, the spots have been 

displaced. By measuring the displacement of spots the wavefront 

distortion can be calculated. An actual spotfield from a Thor Labs 

Shack-Hartmann instrument is shown in Figure 6. A common 

useful visualization of the wavefront distortion is shown in Figure 7. 

Figure 6 

The actual “spotfield” from a Thor 

Labs Shack-Hartmann detector. 

Each spot is the light focused by an 

individual lenslet in a large array of 

lenslets. 

Figure 4 Shack-Hartmann instrument 

To create a simple Shack-Hartmann based wavefront distortion 

detection instrument, only a few components are required. In 

Figure 4, a light source is passed through a pinhole to create a 

point source of light. That point source is collimated into a beam 

using a lens. It is in this collimated beam region that the sample will 

be placed. The light then passes into the Shack-Hartmann sensor. 

There are two important components of the Shack-Hartmann 

sensor: a “lenslet” array (or a “microlens” array) and a camera 

sensor. The lenslet array is a regular, periodic distribution of tiny 

lenses. Usually, the lenslets are arranged into square or rectangular 

array. Behind this array sits the camera sensor. Often this sensor is 

a CCD array, but in principle, a Shack-Hartmann instrument could 

work with any camera – even a film camera. 

Figure 7 

A depiction of TWD data taken from a Thor Labs Shack Hartmann sensor. 

The z-axis shows magnitude of TWD in waves at 633 nm. The axis of x and y 

demonstrates spatial position on the sensor. 

Figure 5 

Light is focused onto a camera sensor inside the Shack-Hartmann detector. Each microlens 

focuses light to a point on the sensor, creating an array of points. In the top diagram, the incident 

light is a perfect plane wave. In the bottom diagram, the wavefront has been distorted. 




37

application note Measuring Transmitted Wavefront Distortion 

Figure 8 

Adding a telescope allows the measured area to be much 

larger than the sensor. 

In a commercial instrument, there are typically refinements made to a basic Shack-Hartmann design. One of the most common refinements 

is to add a telescope after the beam is collimated. 

Adding a telescope (Figure 8) allows the measured area to be much larger than the size of the Shack-Hartmann sensor. Because the price of 

a sensor goes up very quickly with a larger size, it is much more economical to add a telescope than to buy a larger Shack-Hartmann sensor. 

Unfortunately, the addition of a telescope results in a loss in spatial resolution of data points. For example, if the collimated beam width at 

the measured sample is twice as large as the beam width at the sensor, then the data point density is only one-fourth its density without the 

larger collimated beam. However, with high quality optics even a moderate loss in data point density shouldn’t result in severe data corruption 

problems such as aliasing. 

Measuring TWD 

The two most commonly recorded wavefront distortion statistics 

are peak-to-valley wavefront distortion and root-mean-square 

(RMS) wavefront distortion. Peak-to-valley distortion is the difference 

between the most positive and most negative values in the field of 

view. While peak-to-valley distortion only measures the difference 

between two data points, RMS distortion includes all data points in 

its calculation. If our data points are x1, x2, etc., this is computed as: 

We currently employ two Shack Hartmann sensors with capability 

to measure peak-to-valley distortions as small as 1/15th of a 633 

nm wave or RMS distortions as small as 1/50th of a 633 nm wave. 

Another benefit of using a Shack-Hartmann sensor is its ability 

to separate distortion into unique “Zernike coefficients”. Each 

Zernike coefficient corresponds with a specific type of aberration. 

For example, if the sample piece of glass is shaped slightly like 

a bi-concave lens it will exhibit a high value for the “defocus” 

coefficient ( ). The Shack-Hartmann software can distinguish 

aberration corresponding to different coefficients like astigmatism, 

coma, and tilt or spherical. Knowing the relative values of Zernike 

coefficients allows for specific correction of an optic by targeted 

polishing. For example, a common cause of “tilt” is glass that is 

wedge-shaped when viewed on edge. With additional polishing 

it is easy to remedy. Figure 9 shows a graphical depiction of the 

different Zernike coefficients. 

Applications of the 

Shack-Hartmann Instrument 

There two main applications of the Shack-Hartmann at Omega 

Optical; to validate finished product and provide verification that 

specifications have been met, and for performing in process 

manufacturing checks. A product can be measured at various 

points during production pinpointing steps that cause any 

additional wavefront distortion. Once these wavefront adding steps 

are discovered the material can be polished to correct for the 

introduced distortion. 

TWD is one of the most critical interference filter specifications 

for anyone who is concerned with the integrity of the transmitted 

image. Biology and astronomy applications in particular are very 

concerned with image integrity. A TWD error that is imperceptible to 

the human eye in an interference filter could result in an inaccurate 

distance measurement between the moon and a 

planet or between organelles in a cell. With the 

help of a Shack-Hartmann we are certain of 

the quality of the images a filter will produce. 

Figure 9 

A graphical depiction of the Zernike coefficients. 

Applied to an optical piece; red 

indicates a region of positive wavefront 

distortion and blue indicates a region of 

negative wavefront distortion. 

38 




Stock and 

Standard 

products 

For a quick reference to all 

products that can be found in 

this catalog. For application 

specific products, dichroic 

beamsplitters, excitation and 

emission filters see 

pages 66-67. 

The majority of the products we produce are custom manufactured 

to your specifications. 

This capabilities catalog includes our stock products as well as a representation 

of filters assembled from our component inventory defined by industry standard 

specifications. The catalog does not reflect our complete line of products and 

capabilities. 

Stock products are labeled as such throughout the catalog, and are available for 

immediate delivery. 

Standard products are available to ship in 5 business days or less utilizing our 

component inventory. 

UV 

185BP19 XUV185-19 65 

185BP20 XB32 49 

190BP20 XB33 49 

195BP20 XUV195-20 65 

200BP10 XB36 49 

200BP20 XB34 49 

200BP25 XB35 49 

210BP10 XB37 49 

214BP10 XB38 49 

214BP11 XUV214-11 65 

214BP21 XUV214-21 65 

220BP10 XB39 49 

225BP30 XB01 Visit Website 

228BP10 XB40 49 


232BP10 XB41 49 

234.8NB7 XA01 44 

234.9NB7 XA02 44 

239BP10 XB42 49 


249.7NB7 XA03 44 

250BP10 XB43 49 

250BP30 XB02 65 

253.7BP10 XB44 49 

253.7BP12 XUV253.7-12 65 

253.7BP25 XUV253.7-25 65 

255NB7 XA04 44 

260BP10 XB45 49 

265.9NB7 XA05 44 

265BP10 XB47 49 

265BP13 XUV265-13 65 

265BP25 XB46 49 

265BP26 XUV265-26 65 

266BP15 XL01 59 

270BP10 XB48 49 

280BP10 XB50 49 

280BP14 XUV280-14 65 

280BP25 XB49 49 

280BP28 XUV280-28 65 

282NB7 XA06 44 

287.8NB7 XA07 44 

288.2NB7 XA08 44 

289BP10 XB51 49 


296.7BP10 XB52 49 

300BP10 XB53 49 

300BP30 XB03 65 

303.9NB3 XA09 44 

306.8NB7 XA10 44 

310BP10 XB54 49 

313BP10 XB55 49 


322.1NB2 XA11 44 

325NB2 XL02 59 

325NB3 XLK02 60 

326.5NB4 XA12 44 


330WB80 XF1001 73,94 

330WB80 XB04 Visit Website 

331.1NB2 XA13 44 

334BP10 XB56 49 

337BP10 XB57 49 

337NB3 XLK30 60 

340AF15 XF1093 96 

340BP10 XB58 49 

350BP10 XB59 49 

351NB3 XL31 59 

351NB3 XLK31 60 

355NB3 XL03 59 

355NB3 XLK03 60 

360BP10 XB60 49 

360BP50 XB05 65 

364NB4 XL32 59 

364NB4 XLK32 60 


365QM35 XF1409 72,79 

365WB50 XF1005 73,76,80,88,94, 95 

370BP10 XB61 49 

375BP6 XLD375 54 

376BP3 XCC376-3 53 

376BP8 XCC376-8 53 

377NB3 XL30 59 

379.8NB2 XA14 44 

380AF15 XF1094 91,96 

380BP10 XB62 49 

380BP3 XCC380-3 53 

380BP8 XCC380-8 53 

380QM50 XF1415 72,79 

385-485-560TBDR XF2050 78,92 

385-485-560TBEX XF1057 78 

385-502DBDR XF2041 78,91 

386-485-560TBEX XF1059 78 

387AF28 XF1075 73 

390-486-577TBEX XF1458 77 

390-486-577TBEX XF1052 77 

390-486-577TBEX XF1058 78 

390BP10 XB63 49 

396.1NB2 XA15 44 

VISIBLE 

395-540DBDR XF2047 91 

400-477-575TBDR XF2048 78,92 

400-477-580TBEX XF1055 78 

400-485-558-640QBDR XF2046 78,92,95 

400-485-580TBDR XF2045 77,78,79,91,92,95 

400-495-575TBDR XF2051 78,92 

400-495-575TBEX XF1098 78 

400-500DBEX XF1048 78 

400AF30 XF1076 73 

400ALP XF3097 73,94 

400BP10 XB66 49 




39

400DCLP XF2001 72,73,76,79,80,88,94 

400DF15 XF1006 91,92,95 

400DF25 XB65 49 

400DF50 XB64 49 

403.3NB2 XA16 44 

405.4NB3 XB68 49 

405.8NB2 XA17 44 

405-490-555-650QBEX XF1053 78 

405BP10 XB67 49 

405BP3 XCC405-3 53 

405BP6 XLD405 54 

405BP8 XCC405-8 53 

405DF40 XF1008 73,76 

405NB5 XL33 59 

405NB5 XLK33 60 

405QM20 XF1408 79,91 

407.9NB2 XA18 44 

410BP40 XMV410 Visit Website 

410DF10 XB69 49 

410DRLP XF2004 73 

410DRLP XF2085 72,79 

413.8NB2 XA19 44 

415BP3 XCC415-3 53 

415BP8 XCC415-8 53 

415DCLP XF2002 96 

415WB100 XF1301 93 

417.2NB2 XA20 44 

420DF10 XB70 49 

422.7NB2 XA21 44 

424DF44 XCY-424DF44 86 

425DF45 XF1009 73,93,94 

426.5NB4 XA22 44 

426.7NB2 XA23 44 

430DF10 XB71 49 

430NB2 XL34 59 

430NB2 XLK34 60 

432NB2 XA24 44 

435.8BP10 XB72 49 

435.8NB2 XA25 44 

435-546-633 XB29 Visit Website 

435ALP XF3088 73 

435DRLP XF2040 73 

436-510DBDR XF2065 78,92 

436-510DBEX XF1078 78 

436AF8 XF1201 80,92 

436DF10 XF1079 92 

437.9NB2 XA26 44 

439.7NB2 XA27 44 

440AF21 XF1071 73,88,96 

440BP8 XLD440 54 

440DF10 XB73 49 

440QM21 XF1402 72,79 

441.6BP1.9 XLL441.6 57 

442NB2 XA28 44 

442NB2 XL04 59 

442NB2 XLK04 60 

444QMLP XRLP444 55 

445 -535 -658 XB30 Visit Website 

445-510-600TBDR XF2090 92 

445-525-650TBEM XF3061 78,92 

449BP38 XCY-449BP38 86 

450AF65 XF3002 73,80,88,95 

450BP3 XCC450-3 53 

450BP8 XCC450-8 53 

450DCLP XF2006 76 

450DF10 XB76 50 

450DF25 XB75 50 

450DF50 XB74 50 

450QM60 XF3410 72,79 

450WB80 XB08 58 

451.2NB2 XA29 44 

452.5NB2 XA30 44 

455.4NB2 XA31 44 

455DF70 XF1012 73 

455DRLP XF2034 72,73,79,80,88 

457.9BP2 XLL457.9 57 

457/488/514 XB09 Visit Website 

457-528-600TBEM XF3458 77,79,91 

457-528-633TBEM XF3058 78,92 

457NB2 XL05 59 

457NB2 XLK05 60 

458NB5 XA32 44 

460-520-602TBEM XF3063 78,92 

460-520-603-710QBEM XF3059 78,92 

460-550DBEM XF3054 78,91 

460ALP XF3091 73 

460DF10 XB77 50 


465-535-640TBEM XF3118 92 

465AF30 XF3078 73 

467NB2 XA33 44 

470-530-620TBEM XF3116 78,92 

470-590DBEM XF3060 91 

470AF50 XF1087 74,84 

470BP10 XLD470 54 

470DF10 XB78 50 

470QM40 XF1416 72 

470QM50 XF1411 72 

473NB8 XL35 59 

473NB8 XLK35 60 

475-550DBEM XF3099 78,92 

475-625DBDR XF2401 77,91 

475-625DBEX XF1420 77 

475AF20 XF1072 74,88 

475AF40 XF1073 73,74,88 


475DCLP XF2007 73,93,94, 

475QM20 XF1410 72 

477.2NB2 XA34 44 


480AF30 XF3075 73,80,88 

480ALP XF3087 73 

480BP3 XCC480-3 53 

480BP8 XCC480-8 53 

480DF10 XB79 50 

480DF60 XF1014 76 

480QM20 XF1404 91 

480QM30 XF3401 72,79 

481.4NB2 XA35 44 

484-575DBEX XF1451 77 

485-555-650TBDR XF2054 78,92 

485-555-650TBEX XF1063 78 

485-555DBDR XF2039 97 

485-560DBDR XF2443 77,91 

485-560DBEX XF1450 77 

485AF20 XF1202 80 

485DF15 XF1042 91,92,95 

485DF22 XF1015 74,76 

485DRLP XF2027 88 

486.1DF10 XB80 50 

488BP2.1 XLL488 57 

488DF10 XB81 50 

488NB3 XL06 59 

488NB3 XLK06 60 

490-550DBDR XF2043 78,91,95 

490-550DBEX XF1050 78 

490-575DBDR XF2044 77,78,91 

490-577DBEX XF1051 78 


490DF10 XB82 50 

490DF20 XF1011 95,96 

490QM20 XF1406 79,91 

492BP3 XCC492-3 53 

492BP8 XCC492-8 53 


495DF20 XF3005 88 

498.7NB2 XA36 44 

500AF25 XF1068 74,88 

500CFLP XB10 Visit Website 

500DF10 XB85 50 

500DF25 XB84 50 

500DF50 XB83 50 

500DRLP XF2037 74 

500DRLP XF2077 72,74,88 

500QM25 XF1412 72 

500RB100 XB18 Visit Website 

505BP3 XCC505-3 53 

505BP8 XCC505-8 53 

505DRLP XF2010 72,73,74,76,79,80,88 

505DRLPXR XF2031 97 

505DRLPXR XCY-505DRLPXR 86 

509BP21 XCY-509BP21 86 

510AF23 XF3080 74,88 

510ALP XF3086 73,94 

510BP10 XB86 50 

40 




Stock and Standard products 

510BP3 XCC510-3 53 

510BP8 XCC510-8 53 

510DF25 XF1080 92,96 

510QMLP XF3404 72 

510WB40 XF3043 96 

514.5BP2.1 XLL514.5 57 

514.5DF10 XB87 50 

515-600-730TBEM XF3067 78,92 

515ALP XF3093 73 

515DRLP XF2008 73 


515NB3 XL07 59 

515NB3 XLK07 60 

518NB2 XA37 44 

518QM32 XF3405 72 


520-580DBEM XF3056 78,91 

520-610DBEM XF3456 77,91 

520AF18 XF1203 80 

520BP10 XB88 50 

520DF40 XF3003 76 

525-637DBEM XF3457 77,91 

525AF45 XF1074 74,88 

525BP30 XCY-525BP30 86 

525DRLP XF2030 72,74,88 

525QM45 XF1403 72 

525WB20 XF3301 86,93 

528-633DBEM XF3057 78,91 

530ALP XF3082 74 

530BP10 XB89 50 

530DF30 XF3017 80,88 

530QM20 XF3415 79 

530QM40 XF1417 72 

532 /1064 XB11 58 

532/694/1064 XB12 58 

532BP10 XB90 50 

532BP2.2 XLL532 57 

532NB3 XL08 59 

532NB3 XLK08 60 

535.1NB2 XA38 44 

535-710DBEM XF3470 77,91 

535AF26 XF3079 88 

535AF30 XF1103 74 

535AF45 XF3084 74,88,95 

535BP10 XLD535 54 


535DF25 XF3011 96 

535DF35 XF1019 76 

535DF35 XF3007 74,76,88 

535DF45 XCY-535DF45 86 

535QM30 XF1422 79 

535QM50 XF3411 72 


540AF30 XF1077 74,76 

540BP10 XB91 50 

540DCLP XF2013 96 

543.5BP2.4 XLL543.5 57 

543NB3 XL09 59 

543NB3 XLK09 60 

545AF35 XF3074 74,88 

545AF75 XF3105 73,74 

545BP40 XCY-545BP40 86 

545DRLP XF2203 80 

545QM35 XF3407 72 

545QM75 XF3406 72 

546.1BP10 XB92 50 

546.1NB3 XB93 50 

546.6NB2 XA39 44 

546AF10 XF1204 80 

546BP3 XCC546-3 53 

546BP8 XCC546-8 53 

546DF10 XF1020 76 

550-640DBEX XF1062 78 


550CFSP XF85 96 

550DCLP XF2009 76 

550DF10 XB96 50 

550DF25 XB95 50 

550DF30 XCY-550DF30 86 

550DF50 XB94 50 


555-640DBDR XF2053 78 

555DF10 XF1043 91,92,95 

555DRLP XF2062 76,80 

555QM30 XF1405 91 

555QM50 XF1418 72 

560AF55 XF1067 74 

560BP10 XB97 50 

560DCLP XF2016 74,76 

560DF15 XF1045 91,92,95 

560DF40 XF1022 74 

560DRLP XF2017 72,74,79,88 

560DRSP XCY-560DRSP 86 

560QM55 XF1413 72 

561.4BP2.5 XLL561.4 57 

565ALP XF3085 74 


565QMLP XF3408 72 

565WB20 XF3302 80,86,88,93 

568.2BP2.6 XLL568.2 57 

568.2NB3 XB98 50 

568NB3 XL36 59 

568NB3 XLK36 60 

570BP3 XCC570-3 53 

570BP8 XCC570-8 53 

570DF10 XB99 50 

570DRLP XF2015 74,76, 

572AF15 XF1206 80 


574BP26 XCY-574BP26 86 

575ALP XF3089 72 

575DCLP XCY-575DCLP 86 

575DF25 XF1044 76,91,92 

575QM30 XF1407 79,91 

577DF10 XB100 50 

577QM25 XF3416 79 

578BP3 XCC578-3 53 

578BP8 XCC578-8 53 

580AF20 XF1207 80 

580DF10 XB101 50 

580DF30 XF3022 76,80,88,96 

580DRLP XF2086 72 

580QM30 XF1424 79 

585DF22 XCY-585DF22 86 

585QM30 XF3412 72 

585WB20 XF3303 86,93 

589.5NB2 XA40 44 


590DF10 XB102 50 

590DF35 XF3024 76,95 

590DRLP XF2019 74,80 

594NB3 XL10 59 

594NB3 XLK10 60 

595-700DBEM XF3066 78 

595AF60 XF3083 74,88 

595DRLP XF2029 72,74,79,88 

595QM60 XF3403 72 

600BP3 XCC600-3 53 

600BP8 XCC600-8 53 

600CFSP XB22 50 

600DF10 XB105 50 

600DF25 XB104 50 

600DF50 XB103 50 

600DRLP XF2020 74,76,80 

605DF50 XF3019 88 

605WB20 XF3304 86,93 

607AF75 XF1082 75 

610ALP XF3094 74 

610DF10 XB106 50 

610DF20 XF1025 76 

610DF30 XCY-610DF30 86 

610DRLP XF2014 96 

612NB3 XL11 59 

612NB3 XLK11 60 

614BP21 XCY-614BP21 86 

615DF45 XF3025 95 

620BP3 XCC620-3 53 

620BP8 XCC620-8 53 

620DF10 XB107 50 

620DF35 XF3020 80 

625DF20 XF3309 86,93 

625QM50 XF3413 72 

627.8NB2 XA41 44 

630AF50 XF1069 75 

630BP3 XCC630-3 53 




41

630BP8 XCC630-8 53 

630DF10 XB108 50 

630DF22 XCY-630DF22 86 

630DF30 XF3028 76,80 

630DRLP XF2021 76 

630QM36 XF3418 79 

630QM40 XF1421 91 

630QM50 XF1414 72 

632.8BP3 XLL632.8 57 

633 XB23 58 

633NB3.0 XF1026 76 

633NB4 XL12 59 

633NB4 XLK12 60 

635DF55 XF3015 76 

635NB4 XL37 59 

635NB4 XLK37 60 

635QM30 XF1419 72 

636.2NB2 XA42 44 


640AF20 XF1208 80,95 

640BP10 XLD640 54 


640DF10 XB109 50 

640DF20 XF1027 76 

640DF35 XF3023 96 

640DRLP XF2022 76 

640DRLP XCY-640DRLP 86 

640QM20 XF1425 79 

643.9NB2 XA43 44 

645AF75 XF3081 74,76 

645QM75 XF3402 72 

647.1BP3 XLL647.1 57 

647NB4 XL13 59 

647NB4 XLK13 60 

650BP3 XCC650-3 53 

650BP8 XCC650-8 53 

650DF10 XB112 50 

650DF25 XB111 50 

650DF50 XB110 50 

650DRLP XF2035 72,75,76,80 

650DRLP XF2072 75 

650NB5 XL38 59 

650NB5 XLK38 60 



655AF50 XF1095 75 

655DF30 XF1046 92 

655WB20 XF3305 86,93 

655WB25 XLK15 60 

660BP20 XCY-660BP20 86 

660BP3 XCC660-3 53 


660BP8 XCC660-8 53 

660DF10 XB113 50 

660DF35 XCY-660DF35 86 

660DF50 XF3012 76 

660DRLP XF2087 72,79 

665WB25 XL15 59 

670.8NB2 XA44 44 

670DF10 XB114 50 

670DF20 XF1028 75 

670DF40 XF3030 76 


671BP3 XLL671 57 

675DCSPXR XF2033 97 

676NB4 XL14 59 

676NB4 XLK14 60 

677QM25 XF3419 79 

680ASP XF1085 75 

680DF10 XB115 50 


682DF22 XF3031 76,80 

685AF30 XF1096 66,75 

690ALP XF3104 75 

690DF10 XB116 50 

690DRLP XF2024 75 

690DRLP XF2075 75 


692DRLP XF2082 75 

694NB4 XL16 59 

694NB4 XLK16 60 

695AF55 XF3076 75,88,95 

695QM55 XF3409 72 

700ALP XF3095 75 

700BP3 XCC700-3 53 

700BP8 XCC700-8 53 

700CFSP XF86 96 

700DF10 XB119 50 

700DF25 XB118 50 

700DF50 XB117 50 

708DRLP XF2083 75 

710AF40 XF3113 75,86,93 

710ASP XF3100 97 

710DF10 XB120 50 

710DF20 XCY-710DF20 86 

710DF40 XCY-710DF40 86 

710DMLP XCY-710DMLP 86 

710QM80 XF3414 72 

720DF10 XB121 51 

730AF30 XF3114 75 

730DF10 XB122 51 

740ABLP XCY-740ABLP 86 

740DF10 XB123 51 

748LP XCY-748LP 86 

750BP3 XCC750-3 53 

750BP8 XCC750-8 53 

750DF10 XB126 51 

750DF25 XB125 51 

750DF50 XB124 51 

IR 

760DF10 XB127 51 


765DF10 XB128 51 

766.5NB2 XA45 44 

770DF10 XB129 51 

775WB25 XL17 59 

775WB25 XLK17 60 

780BP3.1 XLL780 57 

780DF10 XB130 51 

780DF35 XF117 96 

780NB2 XA46 44 

785BP10 XLD785 54 

785BP3.2 XLL785 57 

785NB4 XL29 59 

785NB4 XLK29 60 

787DF18 XF1211 75 

787DF43 XCY-787DF43 86 



790DF10 XB131 51 


794.7DF1.5 XB134 51 

794.7DF10 XB132 51 

794.7DF3 XB133 51 

800DF10 XB137 51 

800DF25 XB136 51 

800DF50 XB135 51 

800WB80 XF3307 86,93 

805DRLP XF2092 75 

808BP3.7 XLL808 57 

808WB25 XL39 59 

808WB25 XLK39 60 

810DF10 XB138 51 


820DF10 XB139 51 

825WB25 XL18 59 

825WB25 XLK18 60 

830BP3.7 XLL830 57 

830DF10 XB140 51 

830WB25 XL40 59 

830WB25 XLK40 60 


840DF10 XB141 51 

840WB80 XF3308 86,93 

843AF35 XF3121 75 

850DF10 XB144 51 

850DF25 XB143 51 

850DF50 XB142 51 

850WB25 XL19 59 

42 




Stock and Standard products 

850WB25 XLK19 60 

860DF10 XB145 51 

870DF10 XB146 51 

875WB25 XL20 59 

875WB25 XLK20 60 

880DF10 XB147 51 

890DF10 XB148 51 

900DF10 XB151 51 

900DF25 XB150 51 

900DF50 XB149 51 

910DF10 XB152 51 

920DF10 XB153 51 

930DF10 XB154 51 

940DF10 XB155 51 

950DF10 XB158 51 

950DF25 XB157 51 

950DF50 XB156 51 

960DF10 XB159 51 

970DF10 XB160 51 

976BP4 XLL976 57 

980BP4 XLL980 57 

980DF10 XB161 51 

980WB25 XL41 59 

980WB25 XLK41 60 


990DF10 XB162 51 

1000DF10 XB165 52 

1000DF25 XB164 52 

1000DF50 XB163 52 

1010DF10 XB166 52 

1020DF10 XB167 52 

1030BP10 XB168 52 

1040BP10 XB169 52 

1047.1BP1.7 XLL1047.1 57 

1050BP10 XB170 52 

1060BP10 XB171 52 

1060NB8 XL21 59 

1060NB8 XLK21 60 

1064BP1.7 XLL1064 57 

1064NB8 XL22 59 

1064NB8 XLK22 60 

1070BP10 XB172 52 

1076QMLP XRLP1076 55 

1080BP10 XB173 52 

1090BP10 XB174 52 

1100BP10 XB175 52 

1152NB10 XL23 59 

1152NB10 XLK23 60 

1200BP10 XB176 52 

1300BP10 XB177 52 

1310BP10 XB178 52 

1310WB40 XL24 59 

1310WB40 XLK24 60 

1320NB10 XL25 59 

1320NB10 XLK25 60 

1330BP10 XB179 52 

1335QMLP XRLP1335 55 

1350WB40 XL42 59 

1350WB40 XLK42 60 

1400BP10 XB180 52 

1500BP10 XB181 52 

1523NB10 XL26 59 

1523NB10 XLK26 60 

1550NB10 XL28 59 

1550NB10 XLK28 60 

1550WB50 XL27 59 

1550WB50 XLK27 60 

1600BP10 XB182 52 

1650BP10 XB183 52 

1700BP10 XB184 52 

1800BP10 XB185 52 

1900BP10 XB186 52 

2000BP12 XB187 52 

2100BP12 XB188 52 

2200BP12 XB189 52 

2300BP12 XB190 52 

2400BP12 XB191 52 

2500BP12 XB192 52 

ND 0.05 XND0.05 97 

ND 0.1 XND0.1 97 

ND 0.2 XND0.2 97 

ND 0.3 XND0.3 97 

ND 0.4 XND0.4 97 

ND 0.5 XND0.5 97 

ND 0.6 XND0.6 97 

ND 0.7 XND0.7 97 

ND 0.8 XND0.8 97 

ND 1.0 XND1.0 97 

ND 2.0 XND2.0 97 

ND 3.0 XND3.0 97 

OG530 XF3018 76 

OG590 XF3016 76 




43

STANDARD – ANALYTICAL FILTERS 

Narrowband elemental emission line filters 

Designed to work in both arc and spark conditions 

Specific lines chosen for optimal separation from co-existing elements 

Available in 25 diameter 

Custom configurations available upon request 

Analytical Filters 

Element CWL CWL Tolerance FWHM 

FWHM 

Tolerance 

Peak T % 

Average 

Blocking 

Minimum 

Blocking 

Product SKU 

Description 

Beryllium / Be 234.8 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA01 234.8NB7 

Arsenic / As 234.9 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA02 234.9NB7 

Boron / B 249.7 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA03 249.7NB7 

Phosphorus / P 255 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA04 255NB7 

Platinum / Pt 265.9 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA05 265.9NB7 

Hafnium / Ht 282 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA06 282NB7 

Antimony / Sb 287.8 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA07 287.8NB7 

Silicon / Si 288.2 +1.1 -.7 nm 7 ± 1.4 nm 15% OD6 OD3 XA08 288.2NB7 

Germanium / Ge 303.9 +.6 -.4 nm 3 ± .4 nm 15% OD5 OD3 XA09 303.9NB3 

Bismuth / Bi 306.8 +1.1 -7 nm 7 ± 1.4 nm 15% OD5 OD3 XA10 306.8NB7 

Iridium / Ir 322.1 +.5 -.2 nm 2 ± .4 nm 25% OD5 OD3 XA11 322.1NB2 

Copper / Cu 326.5 +.6 -.4 nm 4 ± .8 nm 30% OD5 OD3 XA12 326.5NB4 

Tantalum / Ta 331.1 +.5 -.2 nm 2 ± .4 nm 25% OD5 OD3 XA13 331.1NB2 

Molybdenum / Mo 379.8 +.3 -.2 nm 2 ± .5 nm 25% OD5 OD3 XA14 379.8NB2 

Aluminum / Al 396.1 +.3 -.2 nm 2 ± .4 nm 20% OD OD4 XA15 396.1NB2 

Manganese / Mn 403.3 +.3 -.2 nm 2 ± .4 nm 30% OD5 OD4 XA16 403.3NB2 

Lead / Pb 405.8 +.3 -.2 nm 2 ± .4 nm 30% OD5 OD4 XA17 405.8NB2 

Niobium / Nb 407.9 +.3 -.2 nm 2 ± .4 nm 35% OD5 OD4 XA18 407.9NB2 

Cerium / Ce 413.8 +.3 . nm 2 ± .4 nm 35% OD5 OD4 XA19 413.8NB2 

Gallium / Ga 417.2 +.3 -.2 nm 2 ± .4 nm 35% OD5 OD4 XA20 417.2NB2 

Calcium / Ca 422.7 +.3 -.2 nm 2 ± .4 nm 35% OD5 OD4 XA21 422.7NB2 

Chromium / Cr 426.5 +.6 -.4 nm 4 ± .8 nm 45% OD5 OD4 XA22 426.5NB4 

Carbon / C 426.7 +.3 -.2 nm 2 ± .4 nm 35% OD5 OD4 XA23 426.7NB2 

Tungsten / W 432 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA24 432NB2 

Mercury / Hg 435.8 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA25 435.8NB2 

Vanadium / V 437.9 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA26 437.9NB2 

Iron / Fe 439.7 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA27 439.7NB2 

Nickel / Ni 442 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA28 442NB2 

Indium / In 451.1 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA29 451.2NB2 

Tin / Sn 452.5 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA30 452.5NB2 

Barium / Ba 455.4 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA31 455.4NB2 

Cesium / Cs 458 +.8 -.5 nm 5 ± 1 nm 55% OD5 OD4 XA32 458NB5 

Strontium / Sr 467 +.3 -.2 nm 2 ± .4 nm 45% OD5 OD4 XA33 467NB2 

Zirconium / Zr 477.2 +.3 -.2 nm 2 ± .4 nm 45% OD5 OD4 XA34 477.2NB2 

Cobalt / Co 481.4 +.3 -.2 nm 2 ± .4 nm 40% OD5 OD4 XA35 481.4NB2 

Titanium / Ti 498.7 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA36 498.7NB2 

Magnesium / Mg 518 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA37 518NB2 

Thallium / Tl 535.1 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA38 535.1NB2 

Silver / Ag 546.6 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA39 546.6NB2 

Sodium / Na 589.5 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA40 589.5NB2 

Gold / Au 627.8 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA41 627.8NB2 

Zinc / Zn 636.2 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA42 636.2NB2 

Cadmium / Cd 643.9 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA43 643.9NB2 

Lithium / Li 670.8 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA44 670.8NB2 

Potassium / K 766.5 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA45 766.5NB2 

Rubidium / Rb 780 +.3 -.2 nm 2 ± .4 nm 50% OD5 OD4 XA46 780NB2 

44 




Astronomy filters 

Throughout our history, we have designed and manufactured custom filters and standard prescription filters to the highest 

imaging quality standards for astronomers, atmospheric scientists, and aerospace instrumentation companies worldwide. Applications 

include both terrestrial and space-based observational instruments. We are the supplier of choice for a wide variety 

of prestigious universities, observatories, government agencies, and international consortia. As instrument technologies and 

applications evolve, we work collaboratively with our customers to develop solutions for the spectral, optical, and environmental 

demands that will define observational astronomy and aerospace applications in the future. 

Hubble Space Telescope (HST) 

We have played a key role as the supplier of interference filters throughout the existence of the Wide Field Planetary Camera 2 and 3 (WFPC2, 

WFPC3), in service from 1993 – to date. Our contribution of broad-band and medium band filters, covering the ultraviolet to near infrared 

spectrum, helped extend the world’s view to the furthest reaches of space through observations of the Hubble Deep and Ultra-Deep Fields. 

Closer to home, the now iconic “Pillars of Creation” in the Eagle Nebula, demonstrating star birth in stellar nurseries, was a major achievement 

in astronomical imaging. We are pleased to have been instrumental in the investigation of countless phenomena from galactic super clusters 

to intricate nebulas and the first direct observation of an extra-solar planet. As a supplier of filters for the next generation WFPC3 we are proud 

to continue our support as NASA extends its reach to the edge of the visible universe. 

Mars Rovers 

Our filters continue to explore the Martian landscape on the recently launched Curiosity as well as both the Spirit and Opportunity Rovers. 

The original launch of Spirit and Opportunity utilized a total of 3 sensor systems sending images of Mars in unprecedented clarity. Since 2004 

the "Pancam" has delivered high resolution multispectral images using a total of 16 filters divided between two detectors. Among the many 

mineralogical discoveries, our filters helped prove that water was present on the surface of Mars, furthering the consideration that life may 

have once existed on the red planet. 

Custom Filters & Sets 

Our ability to customize filters for imaging systems sets us apart 

from other filter companies. With over 25 deposition chambers in 

service employing a range of coating technologies from reactive 

sputtering and ion-assisted refractory oxide to physical vapor deposition, 

we have the most important capacity for a filter supplier, 

design flexibility. Below are general guidelines of our capabilities: 

Wavelength Range: 185nm – 2500nm 

Bandwidths: minimum 0.15nm to several hundred nm 

Design Considerations: Critical throughput, 

band-shape and bandwidth requirements 

Size: 2mm – 210mm 

Sets: Matching physical and optical 

performance attributes 

Materials: Space-flight compatible 

High Spectral Performance 

We achieve maximum throughput while adhering to critical bandshape 

tolerances from the UV to NIR. Placement of cut-on/cut-off 

edges are carefully controlled and optical densities in excess of 

OD6 ensure that adjacent spectral regions do not impart noise on 

one another through crosstalk. 

Optical Performance 

As critical to the spectral performance of our filters is the preparation 

and care taken in the choice of substrates. Each filter is polished 

to guarantee optimum image quality. 

Large format filters 

The use of CCD and other large format 

imaging detectors has revolutionized 

the study of astronomy. As both the 

size and sensitivity of these sensors 

have increased, Omega has 

pushed the envelope of coating 

technology to meet the 

need for large format filters 

up to 210mm. Our designs 

achieve the highest 

level of uniformity while 

maintaining the critical 

surface quality and 

transmitted wave-front 

requirements so critical 

to precision imaging. 

Martian surface. 

Photo courtesy of NASA/JPL/Cornell 




45


Photometric Sets 

Common to the astronomy community is the need for precision photometric sets. Omega manufactures a wide range of interference filters for 

color imaging from Bessel, SDSS, and Johnson/Cousins in custom configurations to accommodate specific detector sensitivities. In addition 

to the materials and construction of our photometric sets, filter matching is an important consideration. Consistency between filters in relation 

to band shape, cut-on/cut-off, placement of adjacent spectral regions, throughput, attenuation, sensitivity to system focal ratio, as well as 

operating temperature, is controlled within strict tolerances. 

Bessel Sets 

Omega Optical Bessel Photometric Sets are manufactured to the 

highest optical standards as defined by M. Bessel. In addition to 

our stock Bessel sets, custom filters are available to compensate 

for such aberrations as atmospheric light pollution and dedicated 

imaging applications. 

TWD ¼ wave (or better) per inch 

Wedge


Projects 

Omega Optical has many years of experience designing and 

manufacturing imaging system filters critical to astronomy and 

aerospace applications for organizations such as: 

AURA - Association of Universities 

for Research in Astronomy 

Canadian-France-Hawaii Telescope 

ESA Giotto Mission 

European Southern Observatory Very Large Telescope 

- CONICA - COudé Near Infrared Camera (VLT) 

- OSIRIS 

Canadian Space Agency 

- BRITE- BRIght Target Explorer Constellation 

GRANTECAN 

NASA JPL Star Dust Project 

NASA JPL Hubble Space Telescope 

WFPC2 & WFPC3 

NASA JPL Martian Rovers 

Spirit and Opportunity 

Observatories of the Carnegie Institute 

of Washington 

US Naval Observatory 

Optical Filter Capabilities 

Our filters are used for a wide range of astronomy studies. Following 

is a partial list of products utilized by researchers, universities, 

observatories and government agencies. 

Solar Observation: 

H-alpha 

H-beta 

Nebula and Cometary Studies: 

OII 

OIII 

SII 

CII 

CIII 

IR Astronomy: 

J, H, K Bands 

Photometric Sets 

Bessel (UBVRI) 

Johnson/Cousins (UBVRI) 

Stromgren (UBVY) – Beta Wide & Narrow 

SDSS (u’, g’, r’, l’, z’) 

Thuan-Gunn 

V+R Dual Band Bessel Filter with Light Pollution Supression 

Other 

Detector Compensation 

Harris R 

Mould R-I 

Brian W. Allan, MSc., PhEng. 

shot the M42 nebula using Omega 

Optical’s VHT filter, TeleVue 102 with 

0.8 reducer (700 mm) and 

Canon 50D camera. 




47

Amateur Astronomy filters 

Designed to benefit both visual and CCD imaging, each filter is crafted with the knowledge that every photon 

counts. With this principle in mind, our coatings achieve transmission in excess of 90%, while tightly controlled parallelism and 

transmitted wavefront keep the image crisp and distortion free. Each design also attenuates the critical 540-590nm range where 

light pollution is most prevalent. In eliminating these wavelengths, the contrast between intricate nebulas, faint galaxies and the 

background of space is more apparent. 

Amateur Astronomy filters are available in both 1-1/4” and 2” diameter threaded rings and are housed in a protective case for storage. 

Interference coatings are single-surface, ion beam sputtered for maximum resistance to environmental stress. 

100 

100 

90 

90 

80 

80 

70 

70 

Transmission % 

60 

50 

40 


60 

50 

40 

30 

30 

20 

20 

10 

10 

0 

400 450 500 550 600 650 700 


0 

400 450 500 550 600 650 700 


Measured spectral data for typical VHT filter 

Measured spectral data for typical NPB filter 

100 

Customer Reviews 


80 

60 

40 

20 

0 

400 450 500 550 600 650 


Measured spectral data for typical HPOIII filter 

Please see our website for all options. 

I recently purchased GCE, NPB and VHT filters from 

you. I have used the VHT filter to shoot Orion nebula 

(M42) and it has been my best shot ever! 

Brian, Sundre, Alberta, Canada 

The filter just works. It really does enhance the galactic 

structure and shape. It just does the job. The galaxies I 

looked at really “popped” and did not look like a subtle 

fuzz against bright sky. 

Howard, Cleveland, Ohio 

I am still loving the VHT and NPB filters... they are the 

best... 

Darren, Brisbane, Australia 

48 




Our line of standard interference filters is representative 

of typical industry specifications. Available to ship in 5 business days. 

Need sooner? Please contact us. 

Standard – Bandpass Filters 

Bandpass Filters - UV 

Center Wavelength (nm) FWHM Peak T% Minimum Optical Density Product SKU Description 

185 20 12% 4 XB32 185BP20 

190 20 12% 4 XB33 190BP20 

200 20 12% 4 XB34 200BP20 

200 25 12% 3 XB35 200BP25 

200 10 12% 3 XB36 200BP10 

210 10 12% 3 XB37 210BP10 

214 10 12% 3 XB38 214BP10 

220 10 12% 3 XB39 220BP10 

228 10 12% 3 XB40 228BP10 

232 10 12% 3 XB41 232BP10 

239 10 12% 3 XB42 239BP10 

250 10 12% 3 XB43 250BP10 

253.7 10 12% 3 XB44 253.7BP10 

260 10 12% 3 XB45 260BP10 

265 25 20% 3 XB46 265BP25 

265 10 12% 3 XB47 265BP10 

270 10 12% 3 XB48 270BP10 

280 25 20% 3 XB49 280BP25 

280 10 12% 3 XB50 280BP10 

289 10 12% 3 XB51 289BP10 

296.7 10 12% 3 XB52 296.7BP10 

300 10 12% 3 XB53 300BP10 

310 10 12% 3 XB54 310BP10 

313 10 12% 3 XB55 313BP10 

334 10 25% 3 XB56 334BP10 

337 10 25% 3 XB57 337BP10 

340 10 25% 3 XB58 340BP10 

350 10 25% 3 XB59 350BP10 

360 10 25% 3 XB60 360BP10 

370 10 25% 3 XB61 370BP10 

380 10 25% 3 XB62 380BP10 

390 10 25% 3 XB63 390BP10 

Bandpass Filters - Visible 


400 50 40% 4 XB64 400DF50 

400 25 40% 4 XB65 400DF25 

400 10 35% 4 XB66 400BP10 

405 10 35% 4 XB67 405BP10 

405.4 3 30% 4 XB68 405.4NB3 

410 10 50% 4 XB69 410DF10 

420 10 50% 4 XB70 420DF10 

430 10 50% 4 XB71 430DF10 

435.8 10 50% 4 XB72 435.8BP10 

440 10 60% 4 XB73 440DF10 




49





Bandpass Filters - Visible Continued 


450 50 60% 4 XB74 450DF50 

450 25 60% 4 XB75 450DF25 

450 10 60% 4 XB76 450DF10 

460 10 60% 4 XB77 460DF10 

470 10 60% 4 XB78 470DF10 

480 10 70% 4 XB79 480DF10 

486.1 10 70% 4 XB80 486.1DF10 

488 10 70% 4 XB81 488DF10 

490 10 70% 4 XB82 490DF10 

500 50 70% 4 XB83 500DF50 

500 25 70% 4 XB84 500DF25 

500 10 70% 4 XB85 500DF10 

510 10 70% 4 XB86 510BP10 

514.5 10 70% 4 XB87 514.5DF10 

520 10 70% 4 XB88 520BP10 

530 10 70% 4 XB89 530BP10 

532 10 70% 4 XB90 532BP10 

540 10 70% 4 XB91 540BP10 

546.1 10 70% 4 XB92 546.1BP10 

546.1 3 70% 4 XB93 546.1NB3 

550 50 65% 4 XB94 550DF50 

550 25 65% 4 XB95 550DF25 

550 10 65% 4 XB96 550DF10 

560 10 65% 4 XB97 560BP10 

568.2 3 65% 4 XB98 568.2NB3 

570 10 65% 4 XB99 570DF10 

577 10 65% 4 XB100 577DF10 

580 10 65% 4 XB101 580DF10 

590 10 65% 4 XB102 590DF10 

600 50 65% 4 XB103 600DF50 

600 25 65% 4 XB104 600DF25 

600 10 65% 4 XB105 600DF10 

610 10 65% 4 XB106 610DF10 

620 10 65% 4 XB107 620DF10 

630 10 65% 4 XB108 630DF10 

640 10 65% 4 XB109 640DF10 

650 50 65% 4 XB110 650DF50 

650 25 65% 4 XB111 650DF25 

650 10 65% 4 XB112 650DF10 

660 10 65% 4 XB113 660DF10 

670 10 65% 4 XB114 670DF10 

680 10 65% 4 XB115 680DF10 

690 10 65% 4 XB116 690DF10 

700 50 75% 4 XB117 700DF50 

700 25 75% 4 XB118 700DF25 

700 10 75% 4 XB119 700DF10 

710 10 75% 4 XB120 710DF10 

50 








Bandpass Filters - Visible Continued 


720 10 75% 4 XB121 720DF10 

730 10 75% 4 XB122 730DF10 

740 10 75% 4 XB123 740DF10 

750 50 75% 4 XB124 750DF50 

750 25 75% 4 XB125 750DF25 

750 10 75% 4 XB126 750DF10 

Bandpass Filters - IR 


760 10 75% 4 XB127 760DF10 

765 10 75% 4 XB128 765DF10 

770 10 75% 4 XB129 770DF10 

780 10 75% 4 XB130 780DF10 

790 10 75% 4 XB131 790DF10 

794.7 10 75% 4 XB132 794.7DF10 

794.7 3 75% 4 XB133 794.7DF3 

794.7 1.5 75% 4 XB134 794.7DF1.5 

800 50 75% 4 XB135 800DF50 

800 25 75% 4 XB136 800DF25 

800 10 75% 4 XB137 800DF10 

810 10 75% 4 XB138 810DF10 

820 10 75% 4 XB139 820DF10 

830 10 75% 4 XB140 830DF10 

840 10 75% 4 XB141 840DF10 

850 50 75% 4 XB142 850DF50 

850 25 75% 4 XB143 850DF25 

850 10 75% 4 XB144 850DF10 

860 10 75% 4 XB145 860DF10 

870 10 75% 4 XB146 870DF10 

880 10 75% 4 XB147 880DF10 

890 10 75% 4 XB148 890DF10 

900 50 75% 4 XB149 900DF50 

900 25 75% 4 XB150 900DF25 

900 10 75% 4 XB151 900DF10 

910 10 75% 4 XB152 910DF10 

920 10 75% 4 XB153 920DF10 

930 10 75% 4 XB154 930DF10 

940 10 75% 4 XB155 940DF10 

950 50 75% 4 XB156 950DF50 

950 25 75% 4 XB157 950DF25 

950 10 75% 4 XB158 950DF10 

960 10 75% 4 XB159 960DF10 

970 10 75% 4 XB160 970DF10 

980 10 75% 4 XB161 980DF10 

990 10 75% 4 XB162 990DF10 




51





Bandpass Filters - IR 


1000 50 40% 4 XB163 1000DF50 

1000 25 45% 4 XB164 1000DF25 

1000 10 45% 4 XB165 1000DF10 

1010 10 45% 4 XB166 1010DF10 

1020 10 45% 4 XB167 1020DF10 

1030 10 45% 4 XB168 1030BP10 

1040 10 45% 4 XB169 1040BP10 

1050 10 45% 4 XB170 1050BP10 

1060 10 45% 4 XB171 1060BP10 

1070 10 45% 4 XB172 1070BP10 

1080 10 45% 4 XB173 1080BP10 

1090 10 45% 4 XB174 1090BP10 

1100 10 40% 4 XB175 1100BP10 

1200 10 40% 4 XB176 1200BP10 

1300 10 40% 4 XB177 1300BP10 

1310 10 40% 4 XB178 1310BP10 

1330 10 40% 4 XB179 1330BP10 

1400 10 40% 4 XB180 1400BP10 

1500 10 40% 4 XB181 1500BP10 

1600 10 40% 4 XB182 1600BP10 

1650 10 40% 4 XB183 1650BP10 

1700 10 40% 4 XB184 1700BP10 

1800 10 60% 4 XB185 1800BP10 

1900 10 60% 4 XB186 1900BP10 

2000 12 65% 4 XB187 2000BP12 

2100 12 60% 4 XB188 2100BP12 

2200 12 60% 4 XB189 2200BP12 

2300 12 60% 4 XB190 2300BP12 

2400 12 60% 4 XB191 2400BP12 

2500 12 55% 4 XB192 2500BP12 


Blocking 

Physical 

CWL Range Specification Blocking Range 

185 - 200 nm OD 4 Min. UV to FAR IR 

200 - 313 nm OD 6 Avg. / OD 3 Min. UV to FAR IR 

334 - 390 nm OD 6 Avg. / OD 3 Min. UV to 1,300 nm 

400 - 1,000 nm OD 6 Avg. / OD 4 Min. UV to 1,150 nm 

1,000 - 1,700 nm OD 4 Min. UV to FAR IR 

1,800 - 2,500 nm OD 4 Min. UV to 3,000 nm 

Size 

25, 50, 50 x 50 mm 

Thickness 

< 7.0 mm 

50x50 size is not available for products 

in the following ranges 185 - 313 nm, 

and 1000 - 2500 nm. 


52 




For instrument developers: 

High volume • Extreme performance • Low cost 

Minimum purchase required • Not sold as one-off 

OEM samples available (limited wavelengths) 

QuantaMAX for Clinical Chemistry and 

Biomedical Instrumentation Filters 

QuantaMAX for Clinical Chemistry and Biomedical Instrumentation Filters 

Center Wavelength (nm) Bandwidth (nm) Transmission (Peak) Product SKU Description 

376 3 > 50% XCC376-3 376BP3 

376 8 > 50% XCC376-8 376BP8 

380 3 > 50% XCC380-3 380BP3 

380 8 > 50% XCC380-8 380BP8 

405 3 > 90% XCC405-3 405BP3 

405 8 > 90% XCC405-8 405BP8 

415 3 > 90% XCC415-3 415BP3 

415 8 > 90% XCC415-8 415BP8 

450 3 > 90% XCC450-3 450BP3 

450 8 > 90% XCC450-8 450BP8 

480 3 > 90% XCC480-3 480BP3 

480 8 > 90% XCC480-8 480BP8 

492 3 > 90% XCC492-3 492BP3 

492 8 > 90% XCC492-8 492BP8 

505 3 > 90% XCC505-3 505BP3 

505 8 > 90% XCC505-8 505BP8 

510 3 > 90% XCC510-3 510BP3 

510 8 > 90% XCC510-8 510BP8 

546 3 > 90% XCC546-3 546BP3 

546 8 > 90% XCC546-8 546BP8 

570 3 > 90% XCC570-3 570BP3 

570 8 > 90% XCC570-8 570BP8 

578 3 > 90% XCC578-3 578BP3 

578 8 > 90% XCC578-8 578BP8 

600 3 > 90% XCC600-3 600BP3 

600 8 > 90% XCC600-8 600BP8 

620 3 > 90% XCC620-3 620BP3 

620 8 > 90% XCC620-8 620BP8 

630 3 > 90% XCC630-3 630BP3 

630 8 > 90% XCC630-8 630BP8 

650 3 > 90% XCC650-3 650BP3 

650 8 > 90% XCC650-8 650BP8 

660 3 > 90% XCC660-3 660BP3 

660 8 > 90% XCC660-8 660BP8 

700 3 > 90% XCC700-3 700BP3 

700 8 > 90% XCC700-8 700BP8 

750 3 > 90% XCC750-3 750BP3 

750 8 > 90% XCC750-8 750BP8 


Physical 

Blocking 


Filter Construction 

Size 6 x 6, 10, 12.5 and 15 mm 

Tolerance +0.0/-0.2 mm 

Thickness 2 mm 

OD ≥ 5 average UV-1100 nm 

E/E per MIL-C-48497A 

Single substrate surface coated 


100  

90  

80  

70  

60  

50  

40  

30  

20  

10  

0  

XCC510-8 – actual representation 

XCC510‐8  

460  470  480  490  500  510  520  530  540  550  






53

QuantaMAX Laser Diode 

Clean-Up Filters 

Rejects undesirable diode emissions 

Exceptional transmission >90% 

In the fast growing category of applications and instrumentation that utilize laser sources such as Raman 

Spectroscopy, Confocal and Multiphoton Microscopy, and Flow Cytometry, it is critical to eliminate all unwanted laser background, 

scatter, and plasma in order to optimize signal-to-noise. Laser line and shortpass edge filters can be used to clean-up the signal 

at the laser source. Longpass edge and laser rejection filters can be used for rejecting unwanted noise at the detector. 

Laser Diode Filters are designed to maximize transmission of the primary emission wavelength of the diode, while eliminating secondary 

extended emissions that are typical of laser diodes. The precision plane parallel substrates allow for minimum beam deviation and low 

wavefront error. It is also possible to tilt tune these filters to optimize the peak output of the laser diode/filter combination. 

QuantaMAX Laser Diode Clean-Up Filters 

Laser Diode (nm) T% and Bandwidth Product SKU Description 

375 > 90% over 6 nm XLD375 375BP6 

405 > 90% over 6 nm XLD405 405BP6 

440 > 90% over 8 nm XLD440 440BP8 

470 > 90% over 10 nm XLD470 470BP10 

535 > 90% over 10 nm XLD535 535BP10 

640 > 90% over 10 nm XLD640 640BP10 

785 > 90% over 10 nm XLD785 785BP10 


XLD640 – actual representation 

Physical 

Size 

Thickness 

Stock and custom sizes available 

< 4.0 mm 

8 

7 

Optical Density of XLD640 - actual representation 

Transmission Ripple 

< +/- 1.5% typical 

Angle of Incidence 0.0° +/- 5.0° 

Transmitted Wavefront Error < 0.5 λ over the clear aperture at 633 nm 

Optical 

Transmission 

Density 

(%) 

6 

5 

4 

3 

Beam Deviation 



< 15 arc seconds 



2 

1 

0 

350 400 450 500 550 600 650 700 750 




54 




Improved signal-to-noise 

Excellent laser rejection solution 

QuantaMAX Laser Edge 

Longpass Filters 

Laser Edge Longpass Filters 

Recent developments in sputter coatings have produced a series of QuantaMAX Laser Edge Longpass interference filters to attenuate, or 

block, scattered energy from reaching your detector, therefore improving critical signal-to-noise. 

At the detector, both desired and unwanted scatter will be present, with the signal orders of magnitude lower than the scatter. Scatter is 

the result of minor irregularities and characteristic of the system optics and application, including uncontrolled light from the sample and 

filter holder. Combined with advances in laser and detector technology, our laser edge longpass filters are part of a revolution in Raman 

spectroscopy, expanding the use and applications of this analytical method. 

QuantaMAX Laser Edge Longpass interference filters are an excellent laser rejection solution when used in a collimated light path on 

the detector side of the system. These filters attenuate shorter wavelengths to ~0.7 edge wavelength and transmit 95% of Stokes Raman 

or fluorescence signal and exhibit very high contrast between the Rayleigh and Raman transmission. Angle tuning is required for optimal 

performance. 

QuantaMAX Laser Edge Longpass Filters 

Laser Line (nm) Transmission (Peak) Product SKU Description 


441.6 95% average to 1100 nm XRLP444 444QMLP 

















Physical 

Size 

Stock and custom sizes available 

Thickness 

< 4.0 mm 

Transmission Ripple 

< +/- 1.5% typical 

Blocking 

≥ OD 5 at laser wavelength 

Edge Slope

QuantaMAX Laser Edge 

Longpass Filters 

Angle Tuning Edge Filters 

All edge filters can be angle tuned to achieve optimal signal to noise. 

Angle tuning the filter will blue shift the transmission curve and allow 

Raman signals closer to the laser line to pass through the filter, at 

some expense to blocking, at the laser line. The filter can be oriented 

up to about 15°, normal normal incidence. 

At a 15° angle of incidence, the cut-on wavelength of the longpass 

edge filter will shift blue at approximately 1% of the cut on value 

at normal incidence. A filter that cuts on at 600nm with normal 

orientation will cut on at 594nm when tipped to 15°. A consequence 

of this blue shift is that the blocking at the laser line will decrease by 

approximately 2 levels of optical density. 

A secondary feature of angle tuning is that reflected energy is 

redirected from the optical axis. For longpass edge filters, select a 

filter with an edge that is to the red of the desired cut off and adjust 

the filter angle until optimal performance is achieved. 

For more than 40 years Omega Optical has been a leading 

manufacturer of high performance optical interference filters for a 

wide range of applications in Raman spectroscopy. 

Raman Spectroscopy General Overview 

Raman spectroscopy provides valuable structural information about 

materials. When laser light is incident upon a sample, a small 

percentage of the scattered light may be shifted in frequency. The 

frequency shift of the Raman scattered light is directly related to the 

structural properties of the material. A Raman spectrum provides a 

"fingerprint" that is unique to the material. Raman spectroscopy is 

employed in many applications including mineralogy, pharmacology, 

corrosion studies, analysis of semiconductors and catalysts, in situ 

measurements on biological systems, and even single molecule 

detection. Applications will continue to increase rapidly along with 

further improvements in the technology. A Raman signature provides 

positive material identification of unknown specimens to a degree 

that is unmatched by other spectroscopy's. Raman spectroscopy 

presents demanding requirements for the detection and resolution of 

narrow-bands of light with very low intensity and minimal frequency 

shift relative to the source. We are committed to supporting this 

science with optical coatings of the highest phase thickness and 

resulting superior performance. 

Raman Scattering 

When a probe beam of radiation described by an electric field 

E interacts with a material, it induces a dipole moment, μ, in the 

molecules that compose the material: μ = a x E where a is the 

polarizability of the molecule. The polarizability is a proportionality 

constant describing the deformability of the molecule. In order for 

a molecule to be Raman-active, it must possess a molecular bond 

with a polarizability that varies as a function of interatomic distance. 

Light striking a molecule with such a bond can be absorbed and then 

re-emitted at a different frequency (Raman-shifted), corresponding 

to the frequency of the vibrational mode of the bond. If the molecule 

is in its ground state upon interaction with the probe beam, the light 

can be absorbed and then re-emitted at a lower frequency, since 

energy from the light is channeled into the vibrational mode of the 

molecule. This is referred to as Stokes-shifted Raman scattering. 

If the molecule is in a vibrationally excited state when it interacts 

with the probe beam, the interaction can cause the molecule to give 

up its vibrational energy to the probe beam and drop to the ground 

state. In this case, the scattered light is higher in frequency (shorter 

wavelength than the probe beam). This is referred to as anti-Stokes 

Raman scattering, which under normal conditions is much less 

common than Stokes scattering. The most common occurrence is 

that light is absorbed and re-emitted at the same frequency. This is 

known as Rayleigh, or elastic scattering. 

Both Rayleigh and Raman scattering are inefficient processes. 

Typically only one part in a thousand of the total intensity of incident 

light is Rayleigh scattered, while for Raman scattering this value 

drops to one part in a million. Thus, a major challenge in Raman 

spectroscopy is to attenuate the light that is elastically scattered in 

order to detect the inelastically scattered Raman light. 

Blocking Rayleigh Scattering 

In order to obtain high signal-to-noise in Raman measurements, it 

is necessary to block Rayleigh scattering from reaching the detector 

while transmitting the Raman signal. It's possible to use a double or 

triple grating spectrometer to accomplish rejection of the background 

signal. However, this results in low (~10%) throughput of the desired 

Raman signal. In many cases a better alternative is to use a Raman 

notch or Raman edge filter. Notch filters transmit both Stokes and 

anti-Stokes Raman signals while blocking the laser line. Edge filters 

(also known as barrier filters) transmit either Stokes (longpass) or 

anti-Stokes (shortpass). 

Important considerations in the choice of an edge filter: 

1. How well does the filter block out the Rayleigh scattering? Depending 

on the geometry of the experiment and the sample, blocking of > OD5 

at the laser line is usually sufficient. 

2. How steep is the edge, or transition from blocking to transmitting? 

The steepness of the edge required depends on the laser wavelength 

and the proximity of the Raman shifted signal of interest to the laser 

line. If the laser wavelength is 458nm, one would require > OD5 

blocking at 458nm, and as high as possible transmission only 4nm 

away (at 462nm) in order to see a Stokes mode 200 cm-1 from 

the laser line. If the laser wavelength is 850nm, one would require 

blocking at 850nm and transmission at 865nm (15nm away from the 

laser line) in order to detect a signal at 200cm-1. Therefore, the slope 

of a filter that is required to look at a low frequency mode is steeper 

at bluer laser wavelengths. 

56 




Centered on the laser resonance 

Clean up the unwanted energy 

QuantaMAX Laser Line Filters 

Laser Line Interference Filters 

At the laser source, while output is typically thought of as monochromatic and is described by a prominent line and a single output wavelength, 

there are often lower levels of transitions, plasma and glows, all of which create background errors. Additionally, laser sources can shift in 

wavelength depending on power, temperature and even manufacturing tolerances. Transmitting pure excitation energy requires a laser cleanup 

interference filter to control the unwanted energy. 

Laser line interference filter are narrow bandpass filters centered on the resonance of the laser, that attenuate the background plasma and 

secondary emissions which often results in erroneous signals. In the case of diode lasers and light emitting diodes (LED), our laser line filters 

can be used to make the light output more monochromatic. In the case of gas lasers, these same filters can eliminate plasma in the deep 

blue wavelength region. Laser line interference filters provide 60-90% throughput (the only exception is UV) with spectral control from 0.85 

to 1.15 of the center wavelength (CWL) of the filter. To control a much wider spectral range from the deep UV to the IR an accessory blocker 

can be used. All laser filters are designed with high laser damage thresholds of up to 1 watt/cm 2 . 

QuantaMAX – Laser Line Filters 

Wavelength (nm) Transmission (Peak) Bandwidth (nm) OD5 Range (nm) Product SKU Description 

VISIBLE 

441.6 > 90% 1.7 380 – 700 XLL441.6 441.6BP1.9 

457.9 > 90% 1.7 380 – 700 XLL457.9 457.9BP2 

488.0 > 90% 1.9 380 – 700 XLL488 488BP2.1 

514.5 > 90% 2.0 400 – 770 XLL514.5 514.5BP2.1 

532.0 > 90% 2.0 400 – 770 XLL532 532BP2.2 

543.5 > 90% 2.1 400 – 770 XLL543.5 543.5BP2.4 

561.4 > 90% 2.1 400 – 770 XLL561.4 561.4BP2.5 

568.2 > 90% 2.2 400 – 770 XLL568.2 568.2BP2.6 

632.8 > 90% 2.4 500 – 900 XLL632.8 632.8BP3 

647.1 > 90% 2.5 500 – 900 XLL647.1 647.1BP3 

671.0 > 90% 2.6 500 – 900 XLL671 671BP3 

NEAR INFRARED 

780.0 > 90% 3.0 585 – 1100 XLL780 780BP3.1 

785.0 > 90% 3.0 585 – 1100 XLL785 785BP3.2 

808.0 > 90% 3.1 585 – 1100 XLL808 808BP3.7 

830.0 > 90% 3.2 585 – 1100 XLL830 830BP3.7 

976.0 > 90% 3.7 800 – 1300 XLL976 976BP4 

980.0 > 90% 3.7 800 – 1300 XLL980 980BP4 

1047.1 > 90% 4.0 900 – 1500 XLL1047.1 1047.1BP1.7 

1064.0 > 90% 4.0 900 – 1500 XLL1064 1064BP1.7 

XLL532 – actual representation 

XLL532- actual representation OD 


Physical 

Angle of Incidence 

Transmitted Wavefront Error 

Beam Deviation 



Size 

12.5, 25 and 50 mm 

Thickness 

< 4.0 mm 

0.0° - 10.0° tunable 

< 0.5 λ over the clear aperture at 633 nm 

< 15 arc seconds 




Transmission (%T) 

8 

7 

6 

5 

4 

3 

2 

1 

0 

400 450 500 550 600 650 700 750 800 







57

STANDARD – LASER rejection FILTERS 




Laser Rejection Interference Filters 

At the detector both scatter and signal will be present with the scatter orders of magnitude higher than the signal. To improve signal to noise 

both laser rejection and laser edge filters can be used to attenuate, or block, the scattered energy from reaching the detector. 

Laser rejection filters are designed to block more than 99.9% of light in a 15 to 40 nm bandwidth. The average transmission outside the stopband 

is 75% except in those spectral regions where higher and lower harmonics cause relatively high reflection. Spectrally designed rejection 

band filters reflect more than one spectral band or perform at off normal angles of incidence. Rejection filters provide the ability to measure 

both Stokes and anti-Stokes signals simultaneously and have tunability for variable laser lines. Laser edge filters can also be used for laser 

rejection, providing deeper blocking of the laser line and steeper edges, for small Stokes shifted applications. 

QuanatMAX Laser Edge Filters (see page 53) can also be used for laser rejection, providing deeper blocking of the laser line and steeper 

edges, for small Stokes shifted applications. 

Laser Rejection Filters 

Blocked 

Wavelengths 

457, 488, 514 

Transmission 

(Peak) 

≥ 60% 

Blue, Green and Red 

Optical 

Density 

Product SKU Description Size Thickness Filter Application 

OD3 XB09 457/488/514 25 mm ≤ 3 mm Argon Multi-Line Laser Protection 

532, 1064 ≥ 80% OD4 XB11 532/1064 25 mm ≤ 4 mm Yag & 2nd Yag 

532, 694, 1064 ≥ 75% OD5 XB12 532/694/1064 25 mm ≤ 5 mm Yag, Ruby, 2nd Yag 

632 

≥ 75% 

Blue and Red 

OD3 XB23 633 25 mm ≤ 3 mm HeNe Laser Protection 

Image courtesy of www.biomedcentral.com 


58 







STANDARD – LASER LINE FILTERS 

Laser Line Filters - Limited blocking 

Laser Line CWL CWL Tolerance FWHM FWHM Tolerance 

Transmission 

(Peak) 

Blocking Range Product SKU Description 

4th Nd Yag 266 + 2.2,-1.5 nm 15 ± .3 nm ≥ 20% UV - FIR XL01 266BP15 

HeCd 325 +.3,-.2 nm 2 ± .4 nm ≥ 25% .9 - 1.1 X CWL XL02 325NB2 

N2 337 +.4,-.3 nm 3 ± .6 nm ≥ 40% .85 - 1.15 X CWL XL30 337NB3 

Argon-Ion 351 +.4,-.3 nm 3 ± .6 nm ≥ 60% .85 - 1.15 X CWL XL31 351NB3 

3rd Nd Yag 355 +.4,-.3 nm 3 ± .6 nm ≥ 60% .9 - 1.1 X CWL XL03 355NB3 

Argon 364 +.6,-.4 nm 4 ± .8 nm ≥ 60% .85 - 1.15 X CWL XL32 364NB4 

Blue Diode/DPSS 405 +.6,-.4 nm 5 ± .8 nm ≥ 60% .85 - 1.15 X CWL XL33 405NB5 

Blue Diode/DPSS 430 +.3,-.2 nm 5 ± .4 nm ≥ 60% .85 - 1.15 X CWL XL34 430NB2 

HeCd 442 +.3,-.2 nm 2 ± .4 nm ≥ 60% .85 - 1.15 X CWL XL04 442NB2 


Argon 473 +1.2,-.8 nm 8 ± 1.6 nm ≥ 70% .85 - 1.15 X CWL XL35 473NB8 



2nd Nd Yag 532 +.4,-.3 nm 3 ± .6 nm ≥ 80% .85 - 1.15 X CWL XL08 532NB3 

HeNe Green 543 +.4,-.3 nm 3 ± .6 nm ≥ 80% .85 - 1.15 X CWL XL09 543NB3 

Argon/Argon Krypton 568 +.4,-.3 nm 3 ± .6 nm ≥ 80% .85 - 1.15 X CWL XL36 568NB3 

HeNe Yellow 594 +.4,-.3 nm 3 ± .6 nm ≥ 80% .85 - 1.15 X CWL XL10 594NB3 

HeNe Yellow 612 +.4,-.3 nm 3 ± .6 nm ≥ 80% .85 - 1.15 X CWL XL11 612NB3 

HeNe Red 633 +.6,-.4 nm 4 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL12 633NB4 

Red Diode 635 +.6,-.4 nm 4 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL37 635NB4 

Krypton 647 +.6,-.4 nm 4 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL13 647NB4 

Red Diode 650 +.6,-.4 nm 5 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL38 650NB5 

Krypton 676 +.6,-.4 nm 4 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL14 676NB4 

AlGaAs 665 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% .85 - 1.15 X CWL XL15 665WB25 

RUBY 694 +.6,-.4 nm 4 ± .8 nm ≥ 80% .85 - 1.15 X CWL XL16 694NB4 


Sapphire 785 +0.7, -0.6 nm 4 ± 1 nm ≥ 80% .85 - 1.15 X CWL XL29 785NB4 

Diode 808 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% .85 - 1.15 X CWL XL39 808WB25 


GaAlAs 830 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% .85 - 1.15 X CWL XL40 830WB25 



InGaAs 980 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% .85 - 1.15 X CWL XL41 980WB25 

1st Nd Yag 1060 +1.2,-.8 nm 8 ± 1.6 nm ≥ 85% .85 - 1.15 X CWL XL21 1060NB8 

1st Nd Yag 1064 +1.2,-.8 nm 8 ± 1.6 nm ≥ 80% .85 - 1.15 X CWL XL22 1064NB8 

HeNe IR 1152 +1.5,-1 nm 10 ± 2 nm ≥ 80% .85 - 1.15 X CWL XL23 1152NB10 

InGaAsP 1310 +6,-4 nm 40 ± 8 nm ≥ 80% .85 - 1.15 X CWL XL24 1310WB40 

Nd Yag 1320 +1.5,-1 nm 10 ± 2 nm ≥ 80% .85 - 1.15 X CWL XL25 1320NB10 

Diode 1350 +3.7,-2.5 nm 40 ± 5 nm ≥ 80% .85 - 1.15 X CWL XL42 1350WB40 

HeNe IR 1523 +1.5,-1 nm 10 ± 2 nm ≥ 80% .85 - 1.15 X CWL XL26 1523NB10 

InGaAsP 1550 +7.5,-5 nm 50 ± 10 nm ≥ 80% .85 - 1.15 X CWL XL27 1550WB50 

InGaAsP 1550 +1.5,-1 nm 10 ± 2 nm ≥ 80% .85 - 1.15 X CWL XL28 1550NB10 





59

STANDARD – LASER LINE FILTERS 

Centered on the laser resonance 

Clean up the unwanted energy 

Available in 25 mm diameter 

Laser Line Filters - Fully blocked 

The Transmission (Peak) is a value of an unblocked filter. The addition of a blocking 

component will reduce the Transmission (Peak) by 20%. 

Laser Line CWL CWL Tolerance FWHM FWHM Tolerance 

Transmission 

(Peak) 

Blocking Range Product SKU Description 

HeCd 325 +.3,-.2 nm 2 ± .4 nm ≥ 25% UV - 2500 nm XLK02 325NB2 

N2 337 +.4,-.3 nm 3 ± .6 nm ≥ 40% UV - 2500 nm XLK30 337NB3 

Argon-Ion 351 +.4,-.3 nm 3 ± .6 nm ≥ 60% UV - 2500 nm XLK31 351NB3 

3rd Nd Yag 355 +.4,-.3 nm 3 ± .6 nm ≥ 60% UV - 2500 nm XLK03 355NB3 

Argon 364 +.6,-.4 nm 4 ± .8 nm ≥ 60% UV - 2500 nm XLK32 364NB4 

Blue Diode/DPSS 405 +.6,-.4 nm 5 ± .8 nm ≥ 60% UV - 2500 nm XLK33 405NB5 

Blue Diode/DPSS 430 +.3,-.2 nm 5 ± .4 nm ≥ 60% UV - 2500 nm XLK34 430NB2 

HeCd 442 +.3,-.2 nm 2 ± .4 nm ≥ 60% UV - 2500 nm XLK04 442NB2 


Argon 473 +1.2,-.8 nm 8 ± 1.6 nm ≥ 70% UV - 2500 nm XLK35 473NB8 



2nd Nd Yag 532 +.4,-.3 nm 3 ± .6 nm ≥ 80% UV - 2500 nm XLK08 532NB3 

HeNe Green 543 +.4,-.3 nm 3 ± .6 nm ≥ 80% UV - 2500 nm XLK09 543NB3 

Argon/Argon Krypton 568 +.4,-.3 nm 3 ± .6 nm ≥ 80% UV - 2500 nm XLK36 568NB3 

HeNe Yellow 594 +.4,-.3 nm 3 ± .6 nm ≥ 80% UV - 2500 nm XLK10 594NB3 

HeNe Yellow 612 +.4,-.3 nm 3 ± .6 nm ≥ 80% UV - 2500 nm XLK11 612NB3 

HeNe Red 633 +.6,-.4 nm 4 ± .8 nm ≥ 80% UV - 2500 nm XLK12 633NB4 

Red Diode 635 +.6,-.4 nm 4 ± .8 nm ≥ 80% UV - 2500 nm XLK37 635NB4 

Krypton 647 +.6,-.4 nm 4 ± .8 nm ≥ 80% UV - 2500 nm XLK13 647NB4 

Red Diode 650 +.6,-.4 nm 5 ± .8 nm ≥ 80% UV - 2500 nm XLK38 650NB5 

Krypton 676 +.6,-.4 nm 4 ± .8 nm ≥ 80% UV - 2500 nm XLK14 676NB4 

AlGaAs 665 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% UV - 2500 nm XLK15 665WB25 

RUBY 694 +.6,-.4 nm 4 ± .8 nm ≥ 80% UV - 2500 nm XLK16 694NB4 


Sapphire 785 +0.7, -0.6 nm 4 ± 1 nm ≥ 80% UV - 2500 nm XLK29 785NB4 

Diode 808 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% UV - 2500 nm XLK39 808WB25 


GaAlAs 830 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% UV - 2500 nm XLK40 830WB25 



InGaAs 980 +3.7,-2.5 nm 25 ± 5 nm ≥ 80% UV - 2500 nm XLK41 980WB25 

1st Nd Yag 1060 +1.2,-.8 nm 8 ± 1.6 nm ≥ 85% UV - 1500 nm XLK21 1060NB8 

1st Nd Yag 1064 +1.2,-.8 nm 8 ± 1.6 nm ≥ 80% UV - 1500 nm XLK22 1064NB8 

HeNe IR 1152 +1.5,-1 nm 10 ± 2 nm ≥ 80% UV - 1350 nm XLK23 1152NB10 

InGaAsP 1310 +6,-4 nm 40 ± 8 nm ≥ 80% UV - 1800 nm XLK24 1310WB40 

Nd Yag 1320 +1.5,-1 nm 10 ± 2 nm ≥ 80% UV - 1800 nm XLK25 1320NB10 

Diode 1350 +3.7,-2.5 nm 40 ± 5 nm ≥ 80% UV - 1800 nm XLK42 1350WB40 

HeNe IR 1523 +1.5,-1 nm 10 ± 2 nm ≥ 80% UV - 1800 nm XLK26 1523NB10 

InGaAsP 1550 +7.5,-5 nm 50 ± 10 nm ≥ 80% UV - 1800 nm XLK27 1550WB50 

InGaAsP 1550 +1.5,-1 nm 10 ± 2 nm ≥ 80% UV - 1800 nm XLK28 1550NB10 


60 




Full Width Half Max (FWHM) or bandwidth (BW) of 40 nm 

Transmission >90% 

QuantaMAX Machine Vision 

Filters 

When designing or improving a vision system, light management is a critical consideration. Using optical filters to control 

light selection is a simple and affordable solution to improving contrast, resolution and stability. Historically, photographic filters 

have been used in vision systems, but they lack the desired performance characteristics for today’s systems. 

With many years of experience behind us we have developed 

optical filters for Machine Vision applications with superior physical 

and spectral attributes. Typically produced with robust sputtered 

oxide coatings these filters have a virtually unlimited lifetime as 

they are resistant to heat, humidity, vibration and cleaning solvents. 

The use of single substrates results in low TWD (transmitted 

wavefront distortion). Spectral properties include high in-band 

transmission, deep blocking out of band, and a high level of 

stability. Systems can benefit from the high transmission when 

using lower power LED light sources or viewing faint signals such 

as in fluorescence applications where UV excitation is used to 

view visible fluorescence. LED sources can vary from the specified 

peak output therefore it is important that the bandwidth of the 

filter takes this into consideration. The width of the band as well 

as the wavelength location can also be optimized to accommodate 


“blue shift” associated with viewing light at angles off normal as is 

common in machine vision applications. The controlled passband 

also serves to limit the wavelength range the lens needs to focus on 

resulting in greater resolution. Photographic filters generally block 

light in the region of 400-700 nm in relation to the film which they 

were designed to be used with. Current CCD and CMOS detectors 

have sensitivity from the UV to 1100 nm. Our optical filters for 

Machine Vision provide deep density blocking over this full range 

resulting in greater contrast and stability in changing ambient light 

conditions therefore improving accuracy and speed. 

For these reasons optical filters should be considered a critical 

element in controlling the variable of light in a vision system. 

For assistance in designing the appropriate solution for your 

application, please contact us. We will be happy to assist. 

Omega Optical Filters for Machine Vision 

Physical 

Size 

Thickness 

Transmission > 90 % 

Blocking OD 5 




Stock and custom 

sizes available 

2 mm 



100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

200 400 600 800 1000 


%T 410BP40 

%T 475BP40 

%T 490BP40 

%T 535BP40 

%T 550WB300 

%T 590BP40 

%T 640BP40 

%T 660BP40 

%T 790BP40 

Machine Vision - the Application of Computer Vision and Analysis 

Common uses of the technology span many industries and applications including: 

• Industries: Pharmaceutical, Automotive, Food/Beverage Inspection, Recycling, Life Sciences, Medical Diagnostics, Aerospace, Security. 

• Applications: Image Processing, Biometrics, Printing, Robot Guidance, Pattern Recognition, Diagnostics. 

In many instances, machine vision performs roles previously handled by human beings. Often times, they can be found in inspection systems 

requiring high speed, high magnification, 24-hour operation and/or repeatable measurements. 

Frequently, sensors used in Machine Vision have detection wavelengths over a broad range of the spectrum from the UV through near 

infrared. Without proper filtering and attenuation of unwanted signal, the sensors would be ineffective as the registration of unwanted light 

creates high levels of noise. Interference filters increase the signal to noise ratio allowing for proper discrimination of desired wavelengths 

while blocking all other light. 




61

3 rd Millennium Filters 

Steep slopes 

Specified by the critical cut-on/cut-off edges 

Standard 25 mm diameter off the shelf components 

3 RD Millennium filters are manufactured using Omega Optical’s proprietary 

ALPHA coating technology, a process which produces exceptionally steep cuton 

and cut-off slopes. The result is precise location of cut-on and cut-off 

edges, the ability to place transmission and rejection regions extremely 

close together, and higher attenuation between the passband and the 

rejection band. These filters are produced in custom engineered 

coating equipment that progresses from raw material to complete 

assemblies in a shortened manufacturing cycle. The coating 

chamber is load-locked so that it remains under stable high 

vacuum conditions between coating cycles. 

Control and design of manufacturing processes lead to yield and 

product uniformity 

Short manufacturing cycles results in controlled inventories and 

shorter lead times 

Specifying by the critical cut-on and cut-off edges will result in much 

more accurate band placement and bandwidth. 

Bandpass filters are made using a combination of an ALPHA longpass 

(cut-on) and ALPHA shortpass (cut-off). Longpass and shortpass filters are 

each made using a single surface coating. Passbands can be made wider and 

still achieve the blocking requirements of narrower, less steep designs. Wider 

bandpass filters outperform narrower standard designs with improved transmission, 

deeper blocking, and improved signal-to-noise. 

3 rd Millennium part numbers are unassigned. To order a 3 rd Millennium filter: 

Longpass – specify a cut-on wavelength 

Shortpass – specify a cut-off wavelength 

Bandpass – specify a cut-on & cut-off wavelength 

Example: Product SKU 3RD650LP 

Example: Product SKU 3RD520SP 

Example: Product SKU 3RD580-600 

100 

Actual Transmission 

16 

Typical Optical Density 


14 

80 3 RD Millennium 

Bandpass 

12 

3 RD Millennium 

Bandpass 

60 

10 

Standard 

8 

Fabry Perot 

40 

Bandpass 

6 

4 

20 

2 

0 

500 520 540 560 580 600 



Standard 

Fabry Perot 

Bandpass 

0 

425 475 525 575 625 675 


62 




Steep slopes 

Specified by the critical cut-on/cut-off edges 

Standard 25 mm diameter off the shelf components 



3 rd Millennium filters are offered every 10 nm from 400-700 nm, every 20 nm from 700-800 nm 

and every 50 nm from 800 nm to 1100 nm. 

Filter Type Wavelength Range Transmission Attenuation Range Attenuation 

Longpass Cut-On from 400-700 nm ≥ 90% peak UV to cut-on oD 6 

at every 10 nm 

Cut-On from 700-800 nm 

at every 20nm 

Cut-On from 800-1100 nm 


Shortpass Cut-Off from 400-700 nm ≥ 90% peak Cut-off to 1.3x cut-off OD 6 


Cut-Off from 700-800 nm 


Cut-Off from 800-1100 nm 


Bandpass Cut-On + Cut-Off from ≥ 80% peak UV to 1.3x cut-off oD 6 

400-700 nm 


700-800 nm 


800-1100 nm 


Attenuation Extension: 

When using a silicon detector, in some cases a blocker filter is required to extend the attenuation range to 1100 nm nominally. 

For optimal performance we recommend locating a separate blocking filter in a position remote from the 3 rd Millennium filter. 

Please see page 94 for IR Blocking Filters. 


Physical 

Size 

Thickness 

Clear Aperture 

25 mm 

5.5 mm 

21.3 mm 


Single substrates, air spaced 




63

Photolithography Filters 

i-line Optical Filters 

Omega Optical's new generation i-line filters feature greatly 

improved i-line intensity delivered to the resist, surpassing 

the standard OEM filters. Filters are qualified to the highest 

manufacturing standards, characterized photometrically and 

are packaged in a nitrogen-purged ESD bag. 

These products are designed for litho tools in the 

photolithography process such as LSI and LCD Steppers 

with high power Mercury Lamps. This high performance filter 

resolves monochromatic wavelengths reaching the photomask 

substrate so that optimum resolution is achievable. These 

filters effectively transmit the five lines of the fine structure 

of the Mercury i-line with bandwidth, center wavelength, and 

filter construction designed to allow maximum throughput and 

filter life. 

We offer custom engineered filters as well as standard i-line 

filters. 

Features 

Photometric Performance 

Our i-line filters are thoroughly characterized photometrically. 

The bandpass transmission is evaluated along four radii at 

half inch intervals (125 & 165mm diameter product) using 

a research-grade spectrophotometer. A filter with uniform 

bandpass characteristics across the entire surface yields the 

greatest intensity delivered to the resist. Our filters typically 

exceed intensity levels offered by OEM replacement filters by 

10-20%. 

Photolithography Mask Aligner Filters 

In addition, we offer mask aligner optical filters that provide 

improved exposures and sharper, straighter feature walls of 

the SU-8 photoresist. This filter provides a nominal cut-on 

wavelength of 360nm, blocking shorter wavelengths and 

transmitting the longer wavelengths including the useful 365, 

405 & 436nm mercury lines. It is 90% transparent to visible 

light (or provides 90% transmission), allowing for proper 

visualization of mask alignment through the filter glass. 

These filters are manufactured using durable coatings 

deposited via dual magnetron reactive sputtering to assure 

stability i-line over Filters time and varying environmental conditions. 

Purified Omega fused silica Canon substrates, Filter rather Type than borosilicate, are 

Temperature Typical 

Size CWL Peak T% Q (1/100)* 

used Part Number to assure the Part highest Number optical Bandpass quality and spectral stability. 

Max Lifetime (Hrs) 

2009687 BN-9-7513-000 i-line fi lter 165 mm 365.5 ± 0.6 nm ≥ 90% 2–3 125O C >10,000 


i-line Filters 

2009180 BN-9-6635-000 i-line fi lter FRA/AA 29.9 mm 365.5 ± 1.2 nm ≥ 90% ≤ 2 125O C >10,000 

2008168 Omega Canon g-line Filter fi lter Type 165 mm Temperature Typical 

Size 

436 ± 0.8 

CWL 

nm ≥ 90% 

Peak T% 

2–3 

Q (1/100)* 

125O C >10,000 

Part Number Part Number Bandpass 

Max Lifetime (Hrs) 

2008169 g-line fi lter 124 mm 436 ± 0.8 nm ≥ 90% 2–3 125O C >10,000 


*Note: Defi nition of “Q”: Q(1/100) = 1%BW/FWHM 


2009180 BN-9-6635-000 i-line fi lter FRA/AA 29.9 mm 365.5 ± 1.2 nm ≥ 90% ≤ 2 125O C >10,000 

We currently offer several interference fi lters for step and repeat exposure tools. Continuing development will provide a complete 

product 2008168 line of fi lters for photolithography g-line applications. fi lter 165 Please mmcall us 436 with ± 0.8 requests nm for ≥ custom 90% specifi 2–3 cations. 125O C >10,000 

2008169 g-line fi lter 124 mm 436 ± 0.8 nm ≥ 90% 2–3 125O C >10,000 

Mask Aligner Filters 

2007308 PL-360LP 127 x 127 x 2 mm 

2008110 PL-360LP 165.1 x 165.1 x 2 mm 

2008101 PL-360LP 

Mask Aligner Filters 

171.5 x 171.5 x 2 mm 

2008111 PL-360LP 215.9 x 215.9 x 2 mm 

Omega 

Part Number 

Filter Description 

Dimensions 

*Note: Definition of “Q”: Q(1/100) = 1%BW/FWHM 

We currently offer several interference filters for step and repeat exposure tools. Continuing development will provide a complete 

product Omega line of filters for photolithography applications. Please call us with requests for custom specifi cations. 

Filter Description 

Dimensions 

Note: MicroChem recommends Omega Optical’s PL-360LP optical fi lter 

Part Number 

for use with its SU-8 photoresist. 

Specifications: Mask aligner fi lters are available in a variety 

of sizes to fi t most mask aligner systems. Call with requests 

for custom specifi cations. 

Note: MicroChem recommends Omega Optical’s PL-360LP optical filter 

for use with its SU-8 photoresist. 

We 2007308 offer mask aligner optical PL-360LP interference fi lters 

For current product 

127 that 

listings, 

x 127 provide x 

specifications, 

2 mm improved exposures and sharper, straighter feature walls of the SU-8 

and Specifications: pricing: Mask aligner fi lters are available in a variety 

photoresist. 

2008110 

This fi lter provides 

PL-360LP www.omegafilters.com a nominal cut-on 

165.1 

wavelength • x sales@omegafilters.com 

165.1 x 2 

of 

mm 

360nm, blocking shorter wavelengths and transmitting the longer 

64 wavelengths including the 

of sizes to fi t most mask aligner systems. Call with requests 

1.866.488.1064 useful 365, 405 (toll & 436nm free within mercury USA only) • lines. +1.802.254.2690 It is 90% transparent (outside to USA) visible light, allowing for proper 

2008101 PL-360LP 171.5 x 171.5 x 2 mm 

visualization of mask alignment through the fi lter glass. 

for custom specifi cations.

UV capabilities 

We currently offer UV bandpass filters from 185 nm to 400 nm as triple-cavity MDM (metal dielectric metal) coatings, 

providing extremely high out-of-band attenuation and transmission, as high as the thin film coating materials will allow. Our UV 

filter offer also includes metal shortpass filters with long wavelength attenuation. A filter with OD 4 from the visible and through 

the IR can pass 30% of the shortest UV. 

MDM interference filters are often the most efficient in the UV 

when high S/N is required, due to the long wavelength response of 

typical detectors. Our UV/MDM filters are typically OD5 to OD 8 on 

average. Filters are typically manufactured in single to four cavity 

FP Fabry Perot' designs with precise rectangular passbands. 

Our UV filter range includes high-performance dielectric UV coatings 

as well. These coatings are particularly efficient in throughput 

and provide precise feature wavelength location as well as very 

sharp transmission slope. Bandpass, edge filters (longpasss and 

shortpass) and beamsplitters are among our standard capabilities. 

UV Longpass and Shortpass (edge filters) are currently 

manufactured using our proprietary ALPHA coating technology 

(see page 20). Most commonly used in Raman studies, these 

edge filters typically exhibit peak transmission at > 80% with steep, 

precisely placed edges, blocking the laser in excess of OD4 within 

a few nanometers of an emission region. 

A common approach for the UV/MDM is to use as a pre-filter for 

an all-dielectric passband filter of a few to 10nm in HBW (Half 

bandwidth). With nearly no loss in the dielectric the resulting 

transmission is that of the metal filter. This combination gives 

very low background signal. For ultimate performance in the UV 

a reflection filter will be selected. These filters can pass greater 

than 90% of a UV band, yet attenuate the longer wavelengths to 

OD 4, throughout the longer wavelength regions. Reflection filters 

must be "designed in" solutions, as multiple reflective surfaces are 

required. 

From protected/overcoated Aluminum mirrors, to the most 

effective wide band reflector for the atmospheric window, to 

efficient dielectric selective mirrors, our capabilities in this 

region are broad. Selective reflectors can be built as stop-bands 

with < ± 10 nm bandwidth, to wider bands up to 60 nm in 

width. These coatings can be used at normal incidence or at any 

angle required. Polarization and angle sensitivity are important 

considerations in the design of these products. 

In 2012, this product line will see improvements with the 

introduction of UV interference filters manufactured with sputter 

coating technology; QuantaMAX produced on our Leybold Helios 

systems. Our initial offering will begin with UV filters from 290 nm 

to 400 nm and towards the end of 2012 we expect to produce 

filters closer to 250 nm. 

Whatever your requirement is, large or small, please contact us for 

assistance. We have a large catalog of UV filters available to ship 

within 5 business days. 




65

Fluorescence Filters Reference Table 

Excitation Filters by CWL 

(center wavelength) 

Product SKU Descriptor Page # 

XF1001 330WB80 73,94 

XF1093 340AF15 96 

XF1409 365QM35 72,79 

XF1005 365WB50 73,76,80,88,94, 95 

XF1415 380QM50 72,79 

XF1094 380AF15 91,96 

XF1057 385-485-560TBEX 78 

XF1059 386-485-560TBEX 78 

XF1075 387AF28 73 

XF1458 390-486-577TBEX 77 

XF1052 390-486-577TBEX 77 

XF1058 390-486-577TBEX 78 

XF1055 400-477-580TBEX 78 

XF1098 400-495-575TBEX 78 

XF1048 400-500DBEX 78 

XF1076 400AF30 73 

XF1006 400DF15 91,92,95 

XF1053 405-490-555-650QBEX 78 

XF1408 405QM20 79,91 

XF1008 405DF40 73,76 

XF1301 415WB100 93 

XF1009 425DF45 73,93,94 

XF1078 436-510DBEX 78 

XF1201 436AF8 80,92 

XF1079 436DF10 92 

XF1071 440AF21 73,88,96 

XF1402 440QM21 72,79 

XF1012 455DF70 73 

XF1411 470QM50 72 

XF1087 470AF50 74,84 

XF1416 470QM40 72 

XF1410 475QM20 72 

XF1072 475AF20 74,88 

XF1073 475AF40 73,74,88 

XF1420 475-625DBEX 77 

XF1404 480QM20 91 

XF1014 480DF60 76 

XF1451 484-575DBEX 77 

XF1450 485-560DBEX 77 

XF1063 485-555-650TBEX 78 

XF1202 485AF20 80 

XF1042 485DF15 91,92,95 

XF1015 485DF22 74,76 

XF1406 490QM20 79,91 

XF1050 490-550DBEX 78 

Excitation Filters by CWL 



XF1051 490-577DBEX 78 

XF1011 490DF20 95,96 

XF1412 500QM25 72 

XF1068 500AF25 74,88 

XF1080 510DF25 92,96 

XF1203 520AF18 80 

XF1074 525AF45 74,88 

XF1403 525QM45 72 

XF1417 530QM40 72 

XF1422 530QM30 79 

XF1103 535AF30 74 

XF1019 535DF35 76 

XF1077 540AF30 74,76 

XF1204 546AF18 80 

XF1020 546DF10 76 

XF1062 550-640DBEX 78 

XF1405 555QM25 91 

XF1418 555QM50 72 

XF1043 555DF10 91,92,95 

XF1413 560QM55 72 

XF1067 560AF55 74 

XF1045 560DF15 91,92,95 

XF1022 560DF40 74 

XF1206 572AF15 80 

XF1044 575DF25 76,91,92 

XF1407 575QM30 79,91 

XF1207 580AF20 80 

XF1424 580QM30 79 

XF1082 607AF75 75 

XF1025 610DF20 76 

XF1421 630QM40 91 

XF1414 630QM50 72 

XF1069 630AF50 75 

XF1026 633NB3.0 76 

XF1419 635QM30 72 

XF1425 640QM20 79 

XF1208 640AF20 80,95 

XF1027 640DF20 76 

XF1095 655AF50 75 

XF1046 655DF30 92 

XF1028 670DF20 75 

XF1085 680ASP 75 

XF1096 685AF30 66,75 

XF1211 787DF18 75 

Dichroic Beamsplitters 

by Cut-On 


XF2050 385-485-560TBDR 78,92 

XF2041 385-502DBDR 78,91 

XF2047 395-540DBDR 91 

XF2048 400-477-575TBDR 78,92 

XF2046 400-485-558-640QBDR 78,92,95 

XF2045 400-485-580TBDR 77,78,79,91,92,95 

XF2051 400-495-575TBDR 78,92 

XF2001 400DCLP 72,73,76,79,80,88,94 

XF2004 410DRLP 73 

XF2085 410DRLP 72,79 

XF2002 415DCLP 96 

XF2040 435DRLP 73 

XF2065 436-510DBDR 78,92 

XF2090 445-510-600TBDR 92 

XF2006 450DCLP 76 

XF2034 455DRLP 72,73,79,80,88 

XF2007 475DCLP 73,93,94, 

XF2401 475-625DBDR 77,91 

XF2054 485-555-650TBDR 78,92 

XF2039 485-555DBDR 97 

XF2443 485-560DBDR 77,91 

XF2027 485DRLP 88 

XF2043 490-550DBDR 78,91,95 

XF2044 490-575DBDR 77,78,91 

XF2037 500DRLP 74 

XF2077 500DRLP 72,74,88 

XF2010 505DRLP 72,73,74,76,79,80,88 

XF2031 505DRLPXR 97 

XF2008 515DRLP 73 


XF2030 525DRLP 72,74,88 

XF2013 540DCLP 96 

XF2203 545DRLP 80 

XF2009 550DCLP 76 

XF2053 555-640DBDR 78 

XF2062 555DRLP 76,80 

XF2016 560DCLP 74,76 

XF2017 560DRLP 72,74,79,88 


XF2015 570DRLP 74,76, 

XF2086 580DRLP 72 

XF2019 590DRLP 74,80 

XF2029 595DRLP 72,74,79,88 

XF2020 600DRLP 74,76,80 

XF2014 610DRLP 96 

66 




Dichroic Beamsplitters 

by Cut-On 


XF2021 630DRLP 76 

XF2022 640DRLP 76 

XF2035 650DRLP 72,75,76,80 

XF2072 650DRLP 75 

XF2087 660DRLP 72,79 

XF2033 675DCSPXR 97 

XF2024 690DRLP 75 

XF2075 690DRLP 75 

XF2082 692DRLP 75 

XF2083 708DRLP 75 

XF2092 805DRLP 75 

Emission Filters by CWL 



XF3097 400ALP 73,94 

XF3088 435ALP 73 

XF3061 445-525-650TBEM 78,92 

XF3002 450AF65 73,80,88,95 

XF3410 450QM60 72,79 

XF3458 457-528-600TBEM 77,79,91 

XF3058 457-528-633TBEM 78,92 

XF3063 460-520-602TBEM 78,92 

XF3059 460-520-603-710QBEM 78,92 

XF3054 460-550DBEM 78,91 

XF3091 460ALP 73 

XF3118 465-535-640TBEM 92 

XF3078 465AF30 73 

XF3116 470-530-620TBEM 78,92 

XF3060 470-590DBEM 91 

XF3099 475-550DBEM 78,92 

XF3075 480AF30 73,80,88 

XF3087 480ALP 73 

XF3401 480QM30 72,79 

XF3005 495DF20 88 

XF3080 510AF23 74,88 

XF3404 510QMLP 72 

XF3086 510ALP 73,94 

XF3043 510WB40 96 

XF3067 515-600-730TBEM 78,92 

XF3093 515ALP 73 

XF3405 518QM32 72 

XF3056 520-580DBEM 78,91 

XF3456 520-610DBEM 77,91 

XF3003 520DF40 76 

XF3457 525-637DBEM 77,91 

XF3301 525WB20 86,93 

XF3057 528-633DBEM 78,91 

XF3082 530ALP 74 

XF3415 530QM20 79 

XF3017 530DF30 80,88 

XF3411 535QM50 72 

XF3079 535AF26 88 

XF3084 535AF45 74,88,95 

XF3011 535DF25 96 

XF3007 535DF35 74,76,88 

XF3470 535-710DBEM 77,91 

XF3407 545QM35 72 

XF3074 545AF35 74,88 

XF3406 545QM75 72 

Emission Filters by CWL 



XF3105 545AF75 73,74 

XF3408 565QMLP 72 

XF3085 565ALP 74 

XF3302 565WB20 80,86,88,93 

XF3089 575ALP 72 

XF3416 577QM25 79 

XF3022 580DF30 76,80,88,96 

XF3412 585QM30 72 

XF3303 585WB20 86,93 

XF3024 590DF35 76,95 

XF3066 595-700DBEM 78 

XF3403 595QM60 72 

XF3083 595AF60 74,88 

XF3019 605DF50 88 

XF3304 605WB20 86,93 

XF3094 610ALP 74 

XF3025 615DF45 95 

XF3020 620DF35 80 

XF3413 625QM50 72 

XF3309 625DF20 86,93 

XF3028 630DF30 76,80 

XF3418 630QM36 79 

XF3015 635DF55 76 

XF3023 640DF35 96 

XF3081 645AF75 74,76 

XF3402 645QM75 72 

XF3305 655WB20 86,93 

XF3012 660DF50 76 

XF3030 670DF40 76 

XF3419 677QM25 79 

XF3031 682DF22 76,80 

XF3104 690ALP 75 

XF3409 695QM55 72 

XF3076 695AF55 75,88,95 

XF3095 700ALP 75 

XF3414 710QM80 72 

XF3113 710AF40 75,86,93 

XF3100 710ASP 97 

XF3114 730AF30 75 

XF3307 800WB80 86,93 

XF3308 840WB80 86,93 

XF3121 843AF35 75 

XF3018 OG530 76 

XF3016 OG590 76 




67

Fluorescence Filter setS Reference Table 

Fluorescence Filter Sets Reference Table 

Filter Set SKU Product Category Page # Filter Set SKU Product Category Page # Filter Set SKU Product Category Page # 

XF401 QuantaMAX, M-FISH 72,79 XF13-2 Standard 73 XF305-1 Quantum Dots 93 

XF402 QuantaMAX 72 XF135 Multi-band - Dual 78 XF305-2 Quantum Dots 93 

XF403 QuantaMAX, M-FISH 72,79 XF135-1 Pinkel 92 XF306-1 Quantum Dots 93 

XF404 QuantaMAX 72 XF138-2 Standard 75 XF306-2 Quantum Dots 93 




XF408 QuantaMAX, M-FISH 72,79 XF142-2 Standard 75 XF308-2 Quantum Dots 93 

XF409 QuantaMAX 72 XF148 Standard 75 XF309-1 Quantum Dots 93 

XF410 QuantaMAX 72 XF149 Standard 73 XF309-2 Quantum Dots 93 

XF411 QuantaMAX 72 XF151-2 FRET 88 XF320 Quantum Dots 94 

XF412 QuantaMAX 72 XF152-2 FRET 88 XF32 Standard 76 

XF413 QuantaMAX 72 XF154-1 Pinkel 92 XF35 Standard 76 

XF414 QuantaMAX 72 XF155 Sedat 95 XF37 Standard 76 

XF416 QuantaMAX 72 XF156 Sedat 95 XF38 Standard 76 

XF421 QuantaMAX M-FISH 79 XF157 Sedat 95 XF40-2 Standard 74 

XF422 QuantaMAX M-FISH 79 XF158 FRET 88 XF43 Standard 76 

XF424 QuantaMAX M-FISH 79 XF159 FRET 88 XF45 Standard 76 

XF425 QuantaMAX M-FISH 79 XF16 Ratio Imaging 96 XF46 Standard 76 

XF452 QuantaMAX Dual Band 91 XF160 FRET 88 XF47 Standard 76 

XF453 QuantaMAX Dual Band 77 XF162 FRET 88 XF48-2 Standard 75 

XF454 QuantaMAX Dual Band 77 XF163 FRET 88 XF50 Multi-band - Dual 78 

XF467 QuantaMAX Triple Band 77 XF164 FRET 88 XF50-1 Pinkel 91 

XF452-1 Pinkel 91 XF165 FRET 88 XF52 Multi-band - Dual 78 

XF453-1 Pinkel 91 XF166 FRET 88 XF52-1 Pinkel 91 

XF454-1 Pinkel 91 XF167 FRET 88 XF53 Multi-band - Dual 78 

XF467-1 Pinkel, M-FISH 79,91 XF173 Standard 74 XF53-1 Pinkel 91 

XF02-2 Standard 73,94 XF175 Standard 74 XF56 Multi-band - Triple 78 

XF04-2 Ratio Imaging 96 XF179 Standard 76 XF57 Multi-band - Quad Set 78 

XF05-2 Quantum Dots 73,94 XF18-2 Standard 73 XF57-1 Pinkel 92 

XF06 Standard 73,80 XF201 M-FISH 80 XF59-1 Pinkel 91 

XF09 Standard 76 XF202 M-FISH 80 XF63 Multi-band - Triple 78 

XF100-2 Standard 74 XF203 M-FISH 80 XF63-1 Pinkel 92 

XF100-3 Standard 74 XF204 M-FISH 80 XF66 Multi-band - Triple 78 


XF102-2 Standard 74 XF207 M-FISH 80 XF67-1 Pinkel 92 


XF104-2 Standard 74 XF21 Standard 76 XF68-1 Pinkel 92 

XF105-2 Standard 74 XF23 Standard 74 XF69 Multi-band - Triple 78 

XF106-2 Standard 73 XF25 Standard 76 XF69-1 Pinkel 92 

XF108-2 Standard 74 XF300 Quantum Dots 93 XF72 Ratio Imaging 96 

XF110-2 Standard 75 XF301-1 Quantum Dots 93 XF76 Standard 76 

XF111-2 Standard 74 XF301-2 Quantum Dots 93 XF88-2 FRET 88 

XF114-2 Standard 73 XF302-1 Quantum Dots 93 XF89-2 FRET 88 

XF115-2 Standard 73 XF302-2 Quantum Dots 93 XF92 Multi-band - Dual 78 

XF116-2 Standard 74 XF303-1 Quantum Dots 93 XF93 Multi-band - Triple 78 

XF119-2 Standard 73 XF303-2 Quantum Dots 93 XF93-1 Pinkel 92 

XF130-2 Standard 73 XF304-1 Quantum Dots 93 

XF131 Standard 73 XF304-2 Quantum Dots 93 

68 




QuantaMAX and Standard Filters 

for Fluorescence 

Our fluorescence filter product line is comprised of Stock QuantaMAX and Standard Vivid and Basic 

excitation, emission and dichroic interference filters, and filter sets. 

For the visualization of fluorescence and imaging from deep UV absorbing compounds such as the aromatic amino acids Tyrosine 

and Tryptophan, to near IR absorbing dyes such as Indocyanine Green (ICG) Omega Optical offers a variety of interference filters 

and filter sets We have an impressive history of collaborating with researchers to identify filters that are uniquely compatible with 

specific fluorophores, as well as filters that are effective for fluorophores in a particular experimental design and optical set-up. 

These products are produced utilizing our multiple coating technologies, ion- assist, magnetron sputtering and physical vapor 

deposition, to best match the filter specifications to the application. 

QuantaMAX - Stock Interference Filters 

QuantaMAX are individual excitation, emission and dichroic 

filters and filter sets designed around the most commonly used 

fluorophores used in fluorescence detection and imaging. 

QuantaMAX (QMAX) filters are engineered and manufactured to 

meet the increased demands required of today’s imaging systems. 

Fluorophore Optimized: 

Organic fluorophores, whether a small molecule such as a 

cyanine dye, or a larger mass protein, such as e-GFP, absorb 

and emit photons in a highly wavelength dependent manner. This 

characteristic of a fluorescent compound can be illustrated by its 

specific fluorescence spectral curve, which describes the relative 

probabilities of the absorption and emission of photons across the 

wavelength spectrum. Figure 1 shows the excitation and emission 

curve for Cy5. This fluorophore is widely used in fluorescence 

techniques and exhibits an excitation absorption maximum at 

649nm and emission maximum at 670nm. The slight separation of 

the two is called the Stokes shift and provides a spectral “window” 

through which researchers can (through the use of the appropriate 

interference filters) separate the incoming excitation light from the 

emitted fluorescence. 

deep out of band blocking are considerable, as generating high 

image contrast at low excitation light levels is a desirable condition 

in many protocols, particularly live cell imaging. The ability to place 

the excitation and emission filter pair’s passbands very close to the 

absorption and emission maximums of a particular fluorophore is a 

critical feature for obtaining this contrast. A filter set’s critical edges 

(the facing edges of the excitation and emission filters) are designed 

with a slope of 1% or less to allow for the closest placement of the 

two filters without sacrificing excitation light attenuation. (See figure 

2 and 3) 

QuantaMAX - Stock interference filter sets provide optimal pass 

band placement to achieve efficient specific photon collection 

while simultaneously rejecting stray light and minimizing spectral 

bleed-through from spectrally close fluorophores. 

Figure 2 

Transmission curve of XF407 set for Cy5 

(showing steep edge slope) 

Figure 1 

Excitation and Emission curves of Cy5 

Given the small Stokes Shift of 20 nm or less of many of the typical 

fluorophores used in fluorescence systems, the demands placed 

on the filters to provide high transmission in the passband and 

Substrate Specifications: 

Each filter is produced on a single substrate which has been 

polished to < 15 arc seconds or better. This allows for minimal 

beam deviation and in most imaging systems leads to registrations 

shifts of 1 pixel or less. Excitation and emission filter substrates 

utilize a range of optical substrates which are optimized for low 

light scatter and high transmission through the pass band region of 

the filter. The use of certain high quality absorption glasses in the 




69

QuantaMAX and Standard Filters 

for Fluorescence 

design of these filters also offers the benefit of an increased ability 

to attenuate off axis rays such as those found in instruments using 

high system speeds or less than optimally collimated light sources 

such as light emitting diodes (LED). 

Dichroic mirror substrates utilize UV-grade fused silica to take 

advantage of the high level of internal uniformity of this glass, 

therefore offering excellent transmitted wave-front distortion 

(TWD) and transmission values across the operational range of the 

substrate. 

of contrast is to minimize non-specific light from reaching the 

detector. A typical research grade CCD camera has a quantum 

efficiency range from ~350-1100 nm. By designing each filter 

to offer near band blocking of ≥ OD 6, and extended blocking to 

> OD 5, QMAX filters offer outstanding noise suppression though 

the entire integrated range of the detector. 

Figure 3 

Optical Density curve of XF407 set 

QuantaMAX - Stock filters are available for immediate shipment; 

25 mm round emission and excitation and 25.7 x 36 mm dichroic. 

Additional sizes are available upon request. 

Spectral Performance: 

Single fluorophore QuantaMAX interference filters and filter sets 

provide 90% minimum transmission across the pass-band, and 

routinely exhibit values greater. When using a sensitive detection 

technique such as fluorescence, a key to achieving high levels 


Wavelength 

vivid and basic - Standard interference Filters 

Vivid and Basic - Standard interference filters and filter sets may 

be comprised of our speedy small volume manufacturing process 

or large component inventory. They are not immediately available 

off-the-shelf but are available to ship in 5 business days (expedited 

deliveries are available upon request), and are customized to your 

physical and spectral requirements. Applications involving novel 

fluorophores or multiplexing systems where customized bandwidths 

are a must are examples of where a product from the standard filter 

program can be offered to optimize the system performance. The 

strategy of small lot builds and the incorporation of off-the-shelf 

components provides for filters of nearly any characteristic to be 

produced in a fast and economical fashion. 

Vivid Filters: 

The Vivid product line utilizes a proprietary method of monitoring 

and controlling the coating process. This technology yields filters 

with exceptionally high signal to noise and steep transistion slopes, 

making them suitable for demanding applications. Vivid filters offer 

precise and accurate location of cut on and cut off edges with 

tolerances of +/- 0.01 – +/- 0.05 % of the 50% wavelength edge. 

Basic Filters: 

The Basic filters offer excellent performance at a reasonable 

cost. These filters and filter sets are optimized for the specified 

application and utilize multi-cavity, Fabry-Perot designs to achieve 

a rectangular bandpass shape with very steep edges and deep 

blocking up to OD6 outside the passband. 

Flexible and efficient manufacturing: 

Vivid and Basic - Standard interference filters are assembled from 

our component inventory library of thousands of filter and blockers, 

along with our speedy turn-around manufacturing capabilities, to 

provide solutions for unique applications. Some examples of these 

applications are narrow band Quantum dot specific filters, ratio 

imaging filters, UV activated photo-switchable proteins, along with 

many of the less commonly used fluorophores such as Indocyanine 

Green. These products will meet the requirements for both industry 

and research where a stock catalog part may not provide the ideal 

characteristics for the application and without the added cost of a 

custom manufactured filter and associated lead times. 

Specifications: 

Vivid and Basic - Standard filters are designed to functional 

specifications of the best optical performance at a reasonable 

price and delivery. Typically, standard band-pass excitation filters 

reach minimum 75 % transmission. Standard filters that do not 

require extended blocking can exhibit up to 80-90 % transmission. 

Standard long and short-pass filters will average > 90 % transmission 

over the specified operating spectral range. All imaging filters are 

polished to ≥ 15 arc seconds parallelism and anti-reflection coating 

applied to minimize deviation and reflection. Dichroic mirrors are 

built on the same high quality substrate material as those in the 

stock program for imaging qualities. 

70 




Summary 

Given the vast number of fluorescent dyes and applications in use in laboratories today, a solutions approach to maximizing the available filter 

options has been developed to provide premium performance. QuantaMAX - Stock filters provide precision single substrate coated high 

contrast filters for the most common applications in fluorescence and are available for immediate shipment. Vivid and Basic - Standard filters 

provide a valuable pathway for meeting the requirements of researchers whose needs exist outside the stock program, and want the benefits 

of high contrast, imaging quality fluorescence detection filters at a reasonable cost. 

Omega Optical 




71

QuantaMAX STOCK – 

FLUORESCENCE FILTERS 

Excitation and emission filters: 18, 20, 22, and 25 mm round 

Dichroic beamsplitters: 18 x 26, 20 x 28, 21 x 29, and 25.7 x 36 mm 

rectangular. Dichroics also available as 18, 20, 22, and 25 mm round 

Purchase as sets or as individual components 

QuantaMAX Single Band Filters 

DAPI 

Hoechst 33342 & 33258 

AMCA/AMCA-X 

Alexa Fluor® 350, DAPI, 

Hoescsht 33342 & 33258 

XF408 

Arranged by fluorophores and emission wavelength. 

Dyes Fluorescent Proteins Filter Set SKU Applications Components 

SpectrumAqua® 

Alexa Fluor® 488, Cy2®, 

FITC 

Cy2® 

Fluorescein (FITC) 

Alexa Fluor® 488 


Alexa Fluor® 488, Cy2® 



Cy2®, DiO, Fluo-4 

Rhodamine Green 


Alexa Fluor® 546, 555 

Cy3®, Rhodamine 2, TRITC 

TRITC 

Cy3®, Alexa Fluor® 555 

MitoTracker® Orange 

TRITC, Alexa Fluor® 555 

Cy3®, MitoTracker® Orange 

Alexa Fluor® 568, 594 

Mito-Tracker® Red 

Texas Red®/Texas Red®-X 

Cy3.5® 

MitoTracker® Red 

Optimized for Hg lamp. Narrower excitation bandwidth than 

XF403 set. Can decrease phototoxicity of UV light exposure. 

BFP XF403 Wide excitation bandwith filter may cause cellular 

damage in live cell applications. This set is ideal for imaging 

BFP (Blue Fluorescent Protein) and BFP2. 

CFP, eCFP, 

mCFPm, Cerulean, 

CyPet 

eGFP, CoralHue 

Azami Green, Emerald 

XF401 

XF404 

This filter set is designed for optimal signal capture of 

CFP and to minimize spectral bleedthrough of YFP and 

spectrally similar fluors. 

This set is designed for both excellent brightness and contrast, 

offering ≥ OD 6 at the ex/em crossover. Also designed 

for use in multi-label systems, with minimal excitation of 

dyes such as Texas red and similar fluors. 

eGFP XF409 Longpass emission filter captures highest amounts of 

fluorescent signal, though is not as discriminating as a 

bandpass filter set. Background may be increased. Most 

useful in single label applications. 

CoralHue 

Midoriishi-Cyan, eGFP 

XF410 

Narrowband filters can help to reduce sample 

auto-fluorescence. Useful for discrimination 

from red emitting fluorophores such as mRFP. 

eGFP XF411 This set offers wide passbands for very high brightness 

while still giving good contrast. May exhibit some spectral 

bleedthough with TRITC – like fluorophores. 

YFP, ZsYellow1 XF412 This filter set is optimized for YFP and for minimizing CFP 

bleedthrough. 

Excitation XF1409 365QM35 

Dichroic XF2001 400DCLP 

Emission XF3410 450QM60 


Dichroic XF2085 410DRLP 










Emission XF3404 510QMLP 










DsRed2, mTangerine XF405 Yellow-orange emission for DsRed2, TRITC and others. Excitation XF1417 530QM40 



DsRed2, 

DsRed-Express 

CoralHue Kusabira Orange, 

DsRed2, DsRed-Express, 

mOrange, mTangerine 

XF413 Longpass emission filter. Excitation XF1403 525QM45 


Emission XF3408 565QMLP 

XF402 

High brightness and contrast set for TRITC and similar 

fluors. Offers > OD6 attenuation at the ex/em crossover. 

HcRed, mCherry, Jred XF406 Red emission and good discrimination from 

eGFP in co-expression systems. 

HcRed, HcRed1, 

mRaspberry, MRFP1 

XF414 

Set offers wider passbands than XF406, giving high brightness 

and contrast to red emitting fluors such as Texas Red. 

Alexa Fluor® 647, Cy5® XF407 This set offers a wide emission filter for maximal photon 

capture and a narrower excitation filter for minimizing 

simultaneous excitation of red dyes such as Texas red. 


DiD (DilC18(5)) 

mPlum 

APC (allophycocyanin) 

XF416 

Difficult to see emissions at these 

wavelengths with the unaided eye. B/W camera 

is typically used to capture signal. 

Type Product SKU Description 

















72 






Need sooner? Please call. 

STANDARD – FLUORESCENCE FILTERS 

Vivid Single Band Filters 


Fluorophores Filter Set SKU Applications Components 

DAPI 

Hoechst 33342 & 33258 

AMCA/AMCA-X 

DAPI 

Hoechst 33342 & 33258 

AMCA/AMCA-X 


XF02-2 Wide band excitation filter with longpass emission filter. Excitation XF1001 330WB80 


Emission XF3097 400ALP 

XF05-2 Good with mercury arc lamp. Excitation XF1005 365WB50 



GeneBLAzer (CCF2) XF106-2 Combines blue and green emission colors. Excitation XF1076 400AF30 



DAPI 

Hoechst 33342 & 33258 

AMCA/AMCA-X 

XF06 Optimized for Hg lamp. Excitation XF1005 365WB50 


Emission XF3002 450AF65 

BFP, LysoSensor Blue (pH5) XF131 Similar narrow UV excitation to XF129-2, but with bandpass 

emission filter. 

Cascade Yellow 


SYTOX® Blue 

Excitation XF1075 387AF28 



XF13-2 Excitation XF1008 405DF40 



Sirius XF149 This filter set is designed for imaging the ultramarine emitting fluorescent 

protein, Sirius. Sirius was first reported as a pH insensitive Excitation XF1005 365WB50 

and photostable derivative mseCFP-Y66F from Aequorea Victoria by 

Tomosugi, Matsuda, Nagai et al in the Nature Methods in May 2009. 

Sirius has the lowest emission wavelength of 424nm among currently 


described fluorescent proteins and has great characteristics 

for use in acidic environments. The fluorescent protein can be used 

as a donor in FRET and dual-FRET experiments. 


Pacific Blue XF119-2 Excitation XF1076 400AF30 



CFP 


CFP 


Fura Red (high calcium) 

DiA (4-Di-16-ASP) 

eGFP, Cy2® 





Lucifer Yellow 

XF130-2 

XF114-2 

Longpass emission filter set for CFP. May exhibit higher background 

than bandpass sets, and have higher bleedthrough from other blue 

light excited fluors such as FITC or eGFP. 

Narrow bandpass excitation filter specific for CFP. Designed to 

minimize co-excitation of YFP. 







XF18-2 Broad excitation filter. Excitation XF1012 455DF70 



XF115-2 Longpass emission filter may show more auto-fluorescence. Excitation XF1073 475AF40 



XF14-2 

Set designed for large Stoke’s shift fluors with green emission, such 

as Alexa 430 and Mithramiycin. Wide bandpass emission filter for 

capturing majority of fluorescence photons. 

Excitation XF1009 425DF45 







73






Vivid Single Band Filters Continued 

eGFP 


Alexa Fluor® 488, Cy2® 

XF116-2 



eGFP, Fluorescein (FITC) 



eGFP, Fluorescein (FITC) 



YFP 





Cy2®, BODIPY® FL 

YFP 



XF100-2 

XF100-3 

Narrowband filters can help to reduce sample auto-fluorescence. 

Also useful for discriminating from red emitting fluorophores such 

as mRFP. 

High transmission and good contrast set for FITC, eGFP like fluors. 

Exhibiting steep slopes and good out of band blocking. 

This set consists of wide bandpass filters for collecting maximal 

excitation and emission energy. 










XF105-2 Longpass emission filter set for YFP. Excitation XF1068 500AF25 



XF23 Better photopic color rendition. Excitation XF1015 485DF22 


Emission XF3007 535DF35 

XF104-2 

Optimized filter set for YFP. Excellent contrast set with good 

discrimination for CFP. 

DsRed2 XF111-2 Long pass emission filter for red fluorophors. 

Can provide more signal than bandpass emission filter, though 

background may increase. 







TRITC 

XF101-2 Longpass emission filter. Excitation XF1074 525AF45 





tdTomato XF173 Excitation XF1103 535AF30 



TRITC, Alexa Fluor® 555 

Cy3®, DsRed2 


XRITC Cy3.5®, 

MitoTracker® Red SNARF®-1 

(high pH), Alexa Fluor® 568/594 


Cy3.5® 

MitoTracker® Red 

XF108-2 

XF40-2 

XF102-2 

High brightness and contrast set for TRITC, Cy3 

and similar dyes. 

Longpass emission filter set for XRITC, 5-ROX, and Cy3.5. Brighter 

emission with lower signal to noise than XF41 bandpass equivalent. 

This set is designed for high brightness and contrast. 

Optimized for Texas Red, Alexa 594 and similar dyes. 










mCherry XF175 Excitation XF1067 560AF55 



Propidium Iodide 

Ethidium bromide 

Nile Red 

XF103-2 

Wide passband filter set is designed for high 

brightness and contrast. Will provide higher PI signal than XF179. 






74 






Need sooner? Please call. 


Vivid Single Band Filters Continued 




ICG (Indocyanine Green) XF148 The use the ICG fluorescence method for monitoring of hepatic 

funtion and liver blood flow has become a popular technique in 

recent years. This filter set allows for imaging of ICG without 

interference from hemoglobin or water absorption. 




Alexa Fluor® 660/680, Cy5.5® XF138-2 Best with Red Diode & HeNe lasers. Excitation XF1085 680ASP 





DiD (DilC18(5)) 

XF110-2 

It is very difficult to see emissions at these wavelengths with the 

unaided eye. B/W camera is typically used to capture signal. 




Alexa Fluor® 633/647, Cy5® XF140-2 Hg Arc lamp. Excitation XF1082 607AF75 



Alexa Fluor® 680, Cy5.5® XF48-2 Non-visual detection. 

An IR sensitive detector must be used. 

Alexa Fluor® 660/680, Cy5.5® XF141-2 Non-visual detection. 


Alexa Fluor® 700 XF142-2 Non-visual detection. 











XF100-2 

Representation of Typical Standard Filter Performance 

100 

90 

80 

70 


60 

50 

40 

30 

20 

10 

XF1073 475AF40 

XF2010 505DRLP 

XF3084 535AF45 

0 

440 490 540 590 640 






75






Basic Single Band Filters 



GFP (sapphire) 




BODIPY® FL 

Fluoro-Gold (high pH) 

Aniline Blue 

TRITC, SpectrumOrange® 



TRITC, SpectrumOrange® 

Cy3®, MitoTracker® Orange 


TRITC, Cy3®, SpectrumOrange® 





Acridine orange (+RNA) 

Di-4 ANEPPS 

Propidium Iodide 

Ethidium bromide 

Nile Red 

XF76 

Set designed for fluors with large Stoke shifts such as Cascade 

Yellow and GFP-Sapphire (T-Sapphire). 





XF25 Excitation XF1015 485DF22 


Emission XF3018 OG530 

XF09 Excellent for multiwavelength work in red. Excitation XF1005 365WB50 



XF37 

XF32 

Similar set to XF145 but with a narrower excitation 

filter centered on the 546nm peak of the mercury lamp. 

This TRITC set has a red shifted emission filter 

which gives compatible dyes a yellow fluorescence. 







XF38 Optimized for Hg Lamp. Excitation XF1020 546DF10 


Emission XF3016 OG590 

XF43 

XF21 

Narrow bandwidth excitation filter is specific for the 577nm output 

peak of the Mercury arc lamp. Good discrimination against green 

and yellow emitting fluors such as FITC/ eGFP and YFP. 

This filter set is designed for imaging large Stoke’s shift fluors with 

red emissions, such Rh414 and Di-4 ANEPPS. 










Propidium Iodide (PI) XF179 Filter set with narrowband excitation filter for PI 


which minimizes cross-excitation of Acridine Orange or other similar 


fluorophores. 



BODIPY® 630/650-X 

CryptoLight CF-2, SensiLight P-3 

Cy5® 

BODIPY® 630/650-X 

Alexa Fluor® 633/647 

Cy5® 

BODIPY® 630/650-X 


XF45 

Narrow band filter set minimizes the excitation of spectrally close 

dyes such as Cy3 and TRITC. 




XF46 Excitation filter optimal for 633 HeNe laser line. Excitation XF1026 633NB3.0 



XF47 

Narrowband emission filter. Black and white camera typically 

needed to capture signal. 





76 




Steep edges 

Exceptional transmission 

High throughput 

Single substrate construction 

QuantaMAX Multi-band Filters 

Multi-band interference filters and sets offer the ability to find, localize, and image two or more colors (fluorophores) 

with one filter set. This is accomplished by combining excitation and emission filters with two, three, or even four transmission 

regions with a dichroic mirror which reflects and transmits the appropriate excitation and emission passbands. 

Complete multi-band sets can be used to screen multiple fusion protein constructs quickly for the presence of fluorescent protein without 

switching between single band filter sets. They can also be used in clinical diagnostic settings where simple screening for green/red colors in 

a genomic hybridization assay can reveal the presence of pathogenic organisms in patient samples. 

These filter sets are capable of capturing two or more colors in one image using a color camera (unless specified as being for visual identification 

only), but are not suitable for use with a black and white camera. 

QuantaMAX Multi-band Filters 


Fluorophores Filter Set SKU Application Components 


FITC/ TRITC 

or eGFP/ DsRed2 

FITC/Texas Red® 

or eGFP/mCherry 

XF452 

XF453 

Excellent contrast and high throughput filter set for green and orange emitting 

fluorophores such as FITC and TRITC. Can also be used with Alexa Fluor® 

488, Cy2, and GFP-like fluorescent proteins, as well as Alexa Fluor®568 and 

tdTomato. 

XF453 is optimized for use with fluorescent proteins eGFP and mCherry. This 

high contrast filter set utilizes the 577nm Mercury peak for efficient excitation 

of red emitting fluorophores and is also compatible with many other common 

fluorophores such as FITC and Texas Red®. 

FITC/ Cy5® XF454 Due to their wavelength separation, FITC and Cy5 make a popular choice 

for dual labeling in a single sample as spectral bleedthrough is virtually 

non-existent. Also ideal for green and far red emitting fluorophores. Other 

compatible dyes are, Alexa Fluor®488, Hylite 488, Oregon Green, Cy2, and Alexa 

Fluor®647, Hylite 647. 

DAPI/FITC/Texas Red(r) 

or BFP/eGFP/mCherry 

XF467 

This filter set is optimized for use with common blue, green, red emitting fluors 

such as DAPI/ FITC/Texas Red® or proteins BFP/eGFP/mCherry. The set can be 

used with visual detection, a CCD camera or color film for image capture. 

Excitation XF1450 485-560DBEX 

Dichroic XF2443 485-560DBDR 

Emission XF3456 520-610DBEM 







Excitation XF1458 390-486-577TBEX 

Dichroic XF2045 400-485-580TBDR 

Emission XF3458 457-528-600TBEM 

XF467-1 Triple Band Set for DAPI/FITC/ Texas Red® 

100 

90 

80 

70 


60 

50 

40 

30 

XF1408 405QM20 

XF1406 490QM20 

XF1407 575QM30 

XF2045 400-485-580TBDR 

XF3458 457-528-600TBEM 

20 

10 

0 

350 400 450 500 550 600 650 700 





77

Standard – Multi-band Filters 





Multi-band Filters 



Dual BanD 

DAPI/FITC 

BFP/eGFP 

XF50 





CFP/YFP XF135 Excitation XF1078 436-510DBEX 



FITC/TRITC 

eGFP/DsRed2 

XF52 Excitation XF1050 490-550DBEX 



FITC/Texas Red® XF53 Excitation XF1051 490-577DBEX 



Cy3®/Cy5® XF92 Excitation XF1062 550-640DBEX 



Triple BanD 

Real time visual detection. Excitation XF1055 400-477-580TBEX 

DAPI/FITC/Texas Red® XF63 



DAPI/FITC/Texas Red® XF56 Real time visual imaging with a CCD camera 

or color film. 




DAPI/FITC/Texas Red® XF67 Real time visual detection. Excitation XF1058 390-486-577TBEX 



DAPI/FITC/TRITC XF66 Real time visual imaging with a CCD camera 

or color film. 




DAPI/FITC/TRITC XF68 Real time visual detection. Excitation XF1059 386-485-560TBEX 



DAPI/FITC/Propidium Iodide XF69 Excitation XF1098 400-495-575TBEX 



FITC/Cy3®/Cy5® XF93 Excitation XF1063 485-555-650TBEX 



Quad BanD 

DAPI/FITC/TRITC/Cy5® 

DAPI/FITC/TRITC/ Alexa Fluor®647 

XF57 

Excitation XF1053 405-490-555-650QBEX 

Dichroic XF2046 400-485-558-640QBDR 

Emission XF3059 460-520-603-710QBEM 


78 




QuantaMAX Filters 

for fish and M-FISH 

NEW in 2012, Omega Optical has introduced filters and filters sets optimized for FISH and M-FISH imaging. 

These new products offer the benefits of our high performance QuantaMAX coating technology such as minimized registration errors and 

outstanding transmission, along with high precise band placement to offer the consistency and sharpness of color required in this application. 

Please see also the Standard – FISH and M-FISH filters and sets on page 80. 

QuantaMAX FISH and M-FISH Filters 


Fluorophores Filter Set SKU Components 

DAPI, Hoechst 33342 & 33258, XF408 Excitation XF1409 365QM35 

AMCA/AMCA-X 



DAPI, Hoechst 33342 & 33258, XF403 Excitation XF1415 380QM50 

AMCA, BFP 



Spectrum Aqua, CFP, Cerulean, XF401 Excitation XF1402 440QM21 

CyPEt 



Spectrum Green, FITC, Cy2 NEW XF421 Excitation XF1406 490QM20 



Spectrum Gold NEW XF422 Excitation XF1422 535QM30 



Spectrum Red NEW XF424 Excitation XF1424 580QM30 



Spectrum Far Red NEW XF425 Excitation XF1425 640QM20 



DAPI/FITC/Texas Red®, or 

DAPI/Spectrum Green/Spectrum Red 


XF467-1 Excitation #1 XF1408 405QM20 

Excitation #2 XF1406 490QM20 




XF422 Filter Set for Spectrum Gold 

XF425 Filter Set for Spectrum Far Red 

100 

100 

90 

90 

80 

80 

70 

70 


60 

50 

40 

XF1422 535QM30 


XF3416 577QM25 


60 

50 

40 

XF1425 640QM20 


XF3418 677QM25 

30 

30 

20 

20 

10 

10 

0 

425 475 525 575 625 675 725 

0 

475 525 575 625 675 725 775 






79

standard Filters 

for fish and M-FISH 

For maximizing multi-color labeling applications 

Steep edges and narrow bandwidth 

FISH and M-FISH Filters 




DAPI, AMCA, Cascade Blue® XF06 Excitation XF1005 365WB50 

SpectrumBlue® 



SpectrumAqua®, CFP, DEAC XF201 Excitation XF1201 436AF8 



SpectrumGreen®, FITC, EGFP, Cy2®, 

Alexa Fluor® 488, Oregon Green® 

488, Rhodamine GreenTM 

SpectrumGold®, Alexa Fluor® 532 

YFP 

Cy3®, TRITC, Alexa Fluor® 546 

5-TAMRA, BODIPY® TMR/X 

SpectrumOrange® 

XF202 Excitation XF1202 485AF20 









Cy3.5® XF206 Excitation XF1206 572AF15 



SpectrumRed®, Texas Red® 

Alexa Fluor® 568, BODIPY® TR/X 


Cy5®, BODIPY® 650/665-X 








80 




FISH and 

M-FISH Imaging 


Interference Filters 

and Fluorescence Imaging 

In an upright microscope, the fluorescence illuminator follows an 

epi-fluorescent path (illumination from above) to the specimen. 

In the pathway is housed the filter blocks containing the dichroic 

mirror, excitation, and emission filters, which work to greatly 

improve the brightness and contrast of the imaged specimens, 

even when multiple fluorochromes are being used. Figure 1 

illustrates the basic setup of the fluorescence illuminator on an 

upright microscope. 

Overview 

The application of in situ hybridization (ISH) has advanced 

from short lived, non-specific isotopic methods, to very 

specific, long lived, and multi-color Fluorescent-ISH probe 

assays (FISH). Improvements in the optics, interference 

filter technology, microscopes, cameras, and data handling 

by software have allowed for a cost effective FISH setup 

to be within reach of most researchers. The application of 

mFISH (multiplex-FISH), coupled to the advances in digital 

imaging microscopy, have vastly improved the capabilities 

for non-isotopic detection and analysis of multiple nucleic 

acid sequences in chromosomes and genes. 

Figure 2 

Figure 1 

XF424 

SpectrumRed ® or TexasRed ® filter set 

XF1424 Excitation 580QM30 

XF2029 Dichroic 595DRLP 

XF3418 Emission 63QM36 

The principle components in the episcopic (reflected illumination) 

pathway consist of the light source (here depicted as a Mercury arc 

lamp), a series of lenses that serve to focus the light and correct 

for optical aberrations as the beam travels towards the filters, 

diaphragms which act to establish proper and even illumination 

of the specimen, and the filter turret which houses the filter sets. 

In the diagram it can be seen schematically how the broad band 

excitation light from the light source is selectively filtered to transmit 

only the green component by the excitation filter in the turret, 

which is in turn reflected by the dichroic mirror to the specimen. 

The red fluorescence emission is then transmitted back through 

the objective lens, through the mirror and is further filtered by the 

emission filter before visualization by eye or camera. 

An expanded view of the filter cube is shown in Figure 2. The 

excitation filter is shown in yellow and the emission filter in red to 

describe a typical bandpass Texas Red filter set. 




81

application note FISH and M-FISH Imaging 

Optical Interference Filter Descriptions 

Bandpass filters can be described in several ways. Most common 

is the Center Wavelength (CWL) and Full Width Half Maximum 

(FWHM) nomenclature, or alternatively, by nominal Cut-on and 

Cut-off wavelengths. In the former, the exciter in Fig. 2 is described 

as a 580AF20 or, a filter with nominal CWL of 580nm and a FWHM 

of 20nm. The half maximum value is taken at the transmission value 

where the filter has reached 50% of its maximum value (Figure 3). 

In the latter scheme, the filter would be described as having a Cuton 

of 570nm and a Cut-off of 590nm, no CWL is declared. The Cuton 

describes the transition from attenuation to transmission of the 

filter along an axis of increasing wavelengths. The Cut-off describes 

the transition from transmission back to attenuation. Both values 

indicate the 50% point of full transmission. 

Cut-on and Cut-off values are also used to describe two types of 

filters known as Longpass filters (Figure 4) and Shortpass filters 

(Figure 5). A longpass filter is designed to reflect and/ or absorb 

light in a specific spectral region, to go into transmission at the Cuton 

value (here 570mn) and transmit light above this over a broad 

wavelength range. A shortpass filter does the reverse, blocking 

the wavelengths of light longer than the Cut-off value for a specific 

distance, and transmitting the shorter wavelengths. It should be 

noted that these reflection and transmission zones do not continue 

indefinitely, but are limited by properties of the coating chemicals, 

coating design, and the physical properties of light. 

Figure 3 

%Transmission 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Figure 4 


100 

90 

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70 

60 

50 

40 

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10 

0 

Typical Bandpass Filter 

450 500 550 600 650 700 


570 Long Pass Filter 

400 500 600 700 800 


Figure 5 

%Transmission 

100 

90 

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60 

50 

40 

30 

20 

10 

0 

650 Short Pass Filter 

375 475 575 675 775 


Specialized Filters for FISH and M-FISH 

The imaging of multiple fluorescent probes requires special 

considerations towards the set-up of the interference filter blocks in 

the microscope turret. One strategy is to use individual filter cubes 

for each probe in the specimen. This is an effective strategy for 

6-color viewing (six being the standard number of filter positions 

in most upright research microscopes), as good spectral isolation 

of the different probe species can be obtained through careful 

filter design. This setup also reduces the potential bleaching of the 

probes by illuminating only one fluorescent species at a time. A 

potential drawback to this setup is image registration shifts caused 

by slight misalignments of the filters, producing a minor beam 

deviation that can be detected when switching between several 

different filter cubes. The dichroic mirror and the emission filter are 

the imaging elements of the filter cube and are the two components 

which can contribute to this effect. 

Another strategy is to utilize single multi-band dichroic mirrors and 

emission filters and separate excitation filters either in an external 

slider or filter wheel. This will preserve the image registration and 

reduce mechanical vibrations, but the trade offs are a reduced 

brightness of the fluorescence, limitations on how many different 

probes can be separated, and reduced dynamic range and 

sensitivity due to the required color CCD camera. 

Fluorescence microscopes typically come equipped with standard 

interference filter sets for the common DAPI stain, FITC, TRITC, 

and Texas Red fluorophores. Standard filter sets typically have 

wideband excitation and emission filters (sometimes using longpass 

emission filters) in order to provide maximum brightness. When 

employing FISH, these standard sets can work well for 2, 3 and 

4 color labeling, but spectral bleed-through can rapidly become a 

problem. For instance, FITC is partially visualized through the Cy3 

filter, and Cy 3.5 can be seen through the Cy 5 filter.2 

Figure 6 depicts five different labeled chromosome pairs, the 

crosstalk between channels is shown by the arrows in the top 

82 




middle and bottom left images. Bottom right panel is an overlaid 

pseudo-colored image of the series. In order to minimize the 

Figure 6 

By incorporating the design strategy of narrow band, steep-edged 

filters, the spectral window for adding multiple fluorescent probes 

widens without the cost of adding emission bleed-though between 

fluorophores. 

Figure 8 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

FITC and Cy3: Narrow band mFISH set for FITC 

400 500 600 


XF1406 Excitation Filter 

XF3415 Emission Filter 

FITC Excitation 

FITC Emission 

Cy 3 Excitation 

Cy3 Emission 

spectral bleed-through of very closely spaced fluorophores in 

multicolor labeling schemes, specialized narrow band filter sets 

are needed. Exciter filters of 10-20nm in bandwidth and emission 

filters of 20-40nm provided the specificity necessary to achieve the 

degree of sensitivity and spectral resolution required in mFISH. 

Figure 7 shows a typical wide band FITC filter set overlaid on the 

excitation and emission peaks of FITC and CY 3. 

Figure 7 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

(Image courtesy of Octavian Henegariu, Yale University) 

400 450 500 550 600 650 





FITC Emission 


Cy3 Emission 

Although the filters are designed for covering a substantial area 

under the absorption and emission curves, there is a significant 

overlap with both the excitation and emission curves of Cy3, thus 

resulting in FITC channel contamination by Cy3. A solution is 

seen in Figure 8, where excitation and emission bands have been 

narrowed to improve the spectral resolution of FITC from Cy3, 

especially in the emission band. By limiting the red edge of the 

emission filter a reduction in the area under the emission curve of 

the Cy3 dye of about 4-fold is achieved. 

This can be seen in Figure 9 where three fluorophores are effectively 

separated within a spectral window of less than 300 nm. A fourth 

fluorophore such as Cy 3.5 could easily be incorporated in this 

scheme, as well in the 570-620nm region, but is omitted to reduce 

congestion. 

Figure 9 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

425 475 525 575 625 675 725 




Cy3 Excitation Filter 

Cy3 Emission Filter 

CY 5 Excitation Filter 

Cy 5 Emission Filter 


FITC Emission 


Cy3 Emission 

Cy5 Excitation 

Cy5 Emission 

The demands on the interference filters required for mFISH are 

such that it is necessary to provide a specific category of products 

which are matched together to make optimal use of the available 

bandwidth for each mFISH fluorophore. Product table on pages 

Page 1 

79-80 shows the Omega Optical series of filter sets for the more 

prevalent fluorophores used in mFISH, along with excitation and 

emission filter bandwidths. Note: all are single fluorophore filter 

sets with the exception of and XF467-1 which use single excitation 

filters for each fluorophore and triple band dichroics and emission 

filters. This setup minimizes registration shift and stage movement 

by requiring only that an external filter slider or wheel be moved 

to excite the different dyes while the multi-band dichroics and 

emission filters are kept stationary in the microscope turret. 




83

application note FISH and M-FISH Imaging 

Conclusion 

The techniques of FISH and mFISH used in conjunction with 

the resolving power and automated digital imaging capabilities 

of the fluorescence microscope offer a powerful combination of 

advantages that stand to benefit many areas of biology, from basic 

research to prenatal disease detection, cancer research, pathology, 

and cytogenetics. 

In the fluorescence microscope, careful consideration of the 

sample and system components is necessary to specify the correct 

interference filters for probe detection. Use of multi-band dichroics 

and emission filters in a stationary turret with single excitation filters 

in an external slider or filter wheel can provide near simultaneous 

probe detection with no registration shift, but there are likely 

compromises in overall brightness, color balance difficulty, and 

reduced resolution of the color CCD camera. If sensitivity, spectral 

resolution, and minimal photo-bleaching are primary concerns, 

single narrow band filter sets with black and white CCD camera 

detection are the best option. Image registration shifts are 

minimized in today’s filters by the use of polished glass substrates. 

The type and number of fluorescent probes also plays a role in the 

optimizing of the interference filters. For a small number of probes 

with adequate spectral separation it is possible to use traditional 

wide bandpass filter sets. In protocols where 5 or 6 probes are 

being used, it is necessary to use fluorophore-specific narrow band 

filter sets to reduce spectral bleed-through. 

As methodologies in FISH and mFISH on the fluorescent microscope 

evolve, so must the software and hardware used to unravel the 

information contained in the specimen. A proper combination of 

interference filters, fluorophores, imaging hardware, and software 

is best for obtaining the resolution and contrast necessary for 

accurate image capture and analysis. 

Troubleshooting 

If there is no image: 

• check that the fluorescence light source is on and the light path 

is clear. Light can usually be seen illuminating the sample unless 

it is below 400nm (DAPI excitation). 

• image is being sent to correct port, camera or eyepiece. 

• correct filter block is in place for the desired fluorophore. 

• if desired fluorophore emission is > than approx. 670nm (Cy5) 

it is not visible by most eyes. If not visible by camera, check that 

there is no IR blocking filter in camera. 

If image has high bleed-through from other fluorophores: 

• make sure the filter set is correct for single dye usage, does not 

contain a longpass emission filter or is not a wide bandpass filter 

set. 

References 

• M. Brenner, T. Dunlay and M. Davidson (n.d.). Fluorescence in situ hybridization: Hardware and software implications in the research laboratory. 

October 7, 2008, Molecular Expressions Microscopy Primer Web http://www.microscopyu.com/articles/fluorescence/insitu/brennerinsitu.html 

• O. Henegariu 2001. Multicolor FISH October 8, 2008 “Tavi’ Page” http://info.med.yale.edu/genetics/ward/tavi/fi12.html 

• R. Johnson D.Sc. 2006. Anti-reflection Coatings, Omega Optical 

84 




FLOW CYTOMETRY FILTERS 

Omega Optical has been central to the development of practical applications of fluorescence in the life sciences 

since 1970. Innovators such as Brian Chance of the University of Pennsylvania worked closely with our technical staff to extend 

the state of the art influorescence interference filters. Following the University's development were early instruments for 

Becton Dickinson and Coulter that brought fluorescence detection to single cells and the advent of flow cytometry. 

The ability of modern multicolor flow cytometers to simultaneously 

measure up to 20 distinct fluorophores and to collect forward and 

side scatter information from each cell allows more high quality data 

to be collected with fewer samples and in less time. The presence of 

multiple fluorescing dyes excited by an increasing number of lasers 

places high demands on the interference filters used to collect and 

differentiate the signals. These filters are typically a series of emission 

filters and dichroic mirrors designed to propagate the scattered 

excitation light and fluorescence signal through the system optics 

and deliver to the detectors. 

Emission Filters 

In multichannel systems, the emission filters’ spectral bandwidths 

must be selected not only to optimize collection of the desired 

fluorescent signal, but also to avoid channel cross talk and to 

minimize the need for color compensation that inevitably results 

from overlapping dye emission spectra. For example, suppose a 

system is being configured to simultaneously count cells that have 

been tagged with a combination of FITC and PE. If either of these 

dyes were used alone, a good choice of emission filter would be a 

530BP50 for FITC and a 575BP40 for PE. see graph 1. 

These wide bands would very effectively collect the emission energy 

of each dye transmitting the peaks and much of each dye’s red tail. 

There is a possibility of two problems if used simultaneously. First, 

there will be signifi cant channel cross talk since the red edge of the 

530BP50 FITC filter would be coincident with the blue edge of the 

575BP40 PE filter. Second, because the red tail of FITC overlaps with 

most of the PE emission, a high percentage of color correction will be 

needed to remove the input that the FITC tail will make to the signal 

recorded by the PE channel. A narrower FITC filter (XCY-525BP30) 

that cuts off at 535 nm would provide good channel separation. 

see graph 2. 

Graph 1 


100 

90 

80 

70 

60 

50 

40 

Possible Filter Configuration for Multi-fluor Analysis 

NON OPTIMIZED 

FITC Emission 

PE Emission 

530BP50 Filter 

575BP40 Filter 

This will not however reduce the need for color compensation. To 

achieve this, a narrower PE filter is required. By moving the blue 

edge of the PE filter to 565 nm and the red edge to 585 nm, 

Omega Optical recommends the resulting XCY-574BP26 filter, which 

transmits the peak of the PE emission spectrum. Because it is more 

selective for PE, it transmits much less of the FITC red tail. The result 

is that the need for compensation due to FITC in the PE channel 

will be greatly reduced. 

The selection of emission band placment and width is made more 

complicated by the presence of multiple excitation lasers. If all 

of the sources are on simultaneously, then in addition to cross talk 

and color compensation concerns, the interference filters will need 

to block all excitation wavelengths to OD5 or greater. If the lasers 

are fired sequentially, the complexity is reduced since each emission 

filter need only provide deep blocking for the laser that is on at the 



particular time a given channel is collecting energy. 

100 

90 

80 

70 

60 

50 

Graph 

40 

2 

30 

20 100 

10 


90 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

Possible 

NON 

Filter 

OPTIMIZED 

Configuration for Multi-fluor Analysis 

OPTIMIZED 


OPTIMIZED 

0 

80 

400 450 0 

500 550 600 650 700 750 

Wavelength 500 (nm) 550 400 450 600 650 700 750 

70 


60 

50 

40 

FITC Emission 

PE Emission 

XCY-525BP30 

XCY-574BP26 

mission 

ssion 

0 Filter 

0 Filter 

30 

20 

10 

0 

400 450 500 550 600 650 700 750 


30 

20 

10 

0 

400 450 500 550 600 650 700 750 


FITC Emission 

PE Emission 

XCY-525BP30 

XCY-574BP26 




85

FLOW CYTOMETRY – EMISSION FILTERS 

Excitation Laser 

Fluorophores Product SKU Description 

DAPI, AMCA, Hoechst 33342 and 32580, Alexa Fluor® 350, Marina Blue® XCY-424DF44 424DF44 

Alexa Fluor® 405, Pacific Blue XCY-449BP38 449BP38 

Pacific Orange XCY-545BP40 545BP40 

405, 457 

or 488 

Quantum Dot Emission Filters 

The 405 laser is optimal for excitation of Quantum Dots, but the 488 line laser can also be used. 

Qdot 525 XF3301 525WB20 

Qdot 565 XF3302 565WB20 

Qdot 585 XF3303 585WB20 

Qdot 605 XF3304 605WB20 

Qdot 625 XF3309 625DF20 

Qdot 655 XF3305 655WB20 

Qdot 705 XF3113 710AF40 

Qdot 800 for single color XF3307 800WB80 

Qdot 800 for multiplexing with Qdot 705 XF3308 840WB80 

488 GFP (for separation from YFP, also for separation from Qdots 545 and higher) XCY-509BP21 509BP21 

GFP, FITC, Alexa Fluor® 488, Oregon Green® 488, Cy2®, ELF®-97, PKH2, PKH67, 

Fluo3/Fluo4, LIVE/DEAD Fixable Dead Cell Stain 

XCY-525BP30 525BP30 

GFP, FITC, Alexa Fluor® 488, Oregon Green® 488, Cy2®, ELF-97, PKH2, PKH67, YFP XCY-535DF45 535DF45 

YFP (for separation from GFP) XCY-550DF30 550DF30 

488 or 532 PE, PI, Cy3®, CF-3, CF-4, TRITC, PKH26 XCY-574BP26 574BP26 

PE, PI, Cy3®, CF-3, CF-4, TRITC, PKH26 XCY-585DF22 585DF22 

Lissamine Rhodamine B, Rhodamine Red, Alexa Fluor® 568, RPE-Texas Red®, Live/Dead 

Fixable Red Stain 

XCY-614BP21 614BP21 



XCY-610DF30 610DF30 



XCY-630DF22 630DF22 

PE-Cy5® XCY-660DF35 660DF35 

532 PE-Cy5.5®, PE-Alexa Fluor® 700 XCY-710DF40 710DF40 

633 APC, Alexa Fluor® 633, CF-1, CF-2, PBXL-1, PBXL-3 XCY-660BP20 660BP20 

Cy5.5®, Alexa Fluor® 680, PE-Alexa Fluor® 680, APC-Alexa Fluor® 680, PE-Cy5.5® XCY-710DF20 710DF20 

Cy7® (for separation from Cy5® and conjugates) XCY-740ABLP 740ABLP 

PE-Cy7®, APC-Cy7® XCY-748LP 748LP 

Cy7®, APC-Alexa Fluor® 750 XCY-787DF43 787DF43 

Flow cytometry filters are manufactured to fit all instruments including models by Accuri, Beckman Coulter, BD 

Biosciences, Bay Bio, ChemoMetec A/S, iCyt, Life Technologies, Molecular Devices, Partec and others. Our flow 

cytometry filters are manufactured with the features required to guarantee excellent performance in cytometry 

applications while keeping the price low. 


86 




FLOW CYTOMETRY – DICHROIC FILTERS 

Dichroic filters must exhibit very steep cut-on edges to split off 

fluorescent signals that are in close spectral proximity. Specifying the reflection 

and transmission ranges of each dichroic in a multichannel system requires 

complete knowledge of all of the emission bands in the system and of their 

physical layout. Most often, obtaining optimal performance requires flexibility 

in the placement of the individual channels and the order in which the various 

signals are split off. 

Filter recommendations for a custom multicolor configuration require a complete 

understanding of the system. This includes the dyes that are to be detected, the laser 

sources that will be exciting the dyes, the simultaneity of laser firings, and the physical 

layout of the detection channels. With this information, optimum interference filters 

can be selected that will provide the highest channel signal, the lowest excitation 

background, channel cross talk and the need for color correction. 

Since the emission spectra of fluorescent dyes tend to be spectrally wide, there is 

considerable spectral overlap between adjacent dyes. This becomes more the case 

as the number of channels is increased and the spectral distance between dyes is 

reduced. The result of this overlap is that the signal collected at a particular channel 

is a combination of the emission of the intended dye and emission contributions 

from adjacent dyes. Color compensation is required to subtract the unwanted signal 

contribution from adjacent dyes. Through our work with researchers in the flow 

cytometry community we have established specific band shape characteristics that 

Polarization is an important parameter in signal 

detection. In an optical instrument that utilizes a highly 

polarized light source such as a laser to generate 

signal in the form of both scatter and fluorescence, 

there will be polarization bias at the detector. Many 

factors such as the instrument’s light source, optical 

layout, detector, mirrors and interference filters affect 

the degree of polarization bias. 

Dichroic mirrors are sensitive to polarization effects 

since they operate at off-normal angles of incidence. 

Omega Optical’s dichroics are designed to optimize 

steep transition edges for the best separation of closely 

spaced fluorophores, while minimizing the sensitivity 

to the polarization state of the incident energy. 

Note to Instrument Designers 

With laser sources, all of the output is linearly 

polarized. The dichroics’ performance will be 

different depending on the orientation of the lasers 

polarization. Omega Optical designs for minimum 

difference between polarization states, though it 

should be expected that the effective wavelength of 

the transition will vary by up to 10nm. Engineers at 

Omega Optical will gladly assist in discussing how to 

address this issue. 

minimize the need for color compensation. By creating narrower pass bands and placing them optimally on emission peaks, we have reduced 

the relative contribution of an adjacent dye to a channel’s signal, thereby producing a purer signal with less need for color compensation. 

Product SKU Application Description 

XCY-505DRLPXR 

Extended reflection longpass; Reflects 451 nm, 457 nm, 477 nm, 488 

nm and UV laser lines, Transmits > 525 nm. 

505DRLPXR 

100 

90 

80 

XCY-505DRLPXR 

XCY-560DRSP Shortpass; Separation of FITC from PE. 560DRSP 

XHC575DCLP Separation of Mithramycin from Ethidium Bromide. 575DCLP 

XCY-640DRLP Separation of APC from dyes with shorter wavelength. 640DRLP 

XCY-680DRLP Separation of PE-Cy5® and PE-Cy5.5. 680DRLP 

XCY-690DRLP Separation of APC from APC-Cy5.5® or APC-Cy7®. 690DRLP 

XCY-710DMLP Separation of PE and Cy5® from PE-Cy5.5® or PE-Cy7®. 710DMLP 

XCY-760DRLP Separation of Cy5.5® from Cy7® and their conjugates. 760DRLP 


70 

60 

50 

40 

30 

20 

10 

0 

350 400 450 500 550 600 



Size 

12.5, 15.8 and 25 mm 

Physical 

Thickness 

Shape 

< 6.7 mm 

Specify round and/or square 

Custom configurations available 

upon request 

Angle of Incidence Specify dichroic AOI 45° or 11.25° 




87

STANDARD – FRET FILTERS 





FRET Filters 



Donor Acceptor 


BFP eGFP XF89-2 Excitation XF1005 365WB50 


Emission 1 XF3002 450AF65 


BFP YFP XF158 Excitation XF1005 365WB50 




BFP DsRed2 XF159 Excitation XF1005 365WB50 



Emission 2 XF3019 605DF50 

CFP YFP XF88-2 Excitation XF1071 440AF21 




CFP DsRed2 XF152-2 Excitation XF1071 440AF21 




Midoriishi Cyan Kusabira Orange XF160 Excitation XF1071 440AF21 



Emission 2 XF3302 565WB20 

eGFP DsRed2 or Rhod-2 XF151-2 Excitation XF1072 475AF20 




FITC TRITC XF163 Excitation XF1073 475AF40 




FITC Rhod-2 or Cy3 XF162 Excitation XF1073 475AF40 




Alexa 488 Alexa 546 or 555 XF164 Excitation XF1087 470AF50 




Alexa 488 Cy3 XF165 Excitation XF1073 475AF40 




YFP TRITC or Cy3 XF166 Excitation XF1068 500AF25 




Cy3 Cy5 or Cy5.5 XF167 Excitation XF1074 525AF45 




88 




Optimizing Filter Sets 

for FRET Applications 


Filters & Microscope Configurations 

The filter components required for FRET experiments are not 

esoteric. As in any fluo rescence microscopy application, an 

excita tion filter is required for exciting the donor fluorophore, 

and a dichroic mirror is required for separating donor excitation 

energy from both donor and acceptor emis sion energy. Unlike 

other fluorescence appli cations, however, two emission filters are 

required, one for the acceptor fluorophore, or FRET emission, 

and one for the donor flu orophore in order to correct for single 

bleed thru. As for choosing specific filters, the same filter components 

and sets can be applicable for FRET as those which are 

matched to specific fluo rophores and used in other single color, 

epi fluorescence applications. 

More important in the selection of filters is an understanding of the 

physical configura tion of the microscope hardware to be used in 

the FRET experiment. At issue are critical experimental variables, 

such as time and image registration. While the ideal set-up may 

not be affordable or available to all researchers interested in 

FRET studies, it is nonetheless important to understand the pros 

and cons of the available hardware and filter set configurations. 

1. Multi-View Configurations 

Most ideal for the viewing and measurement of molecular, proteinprotein 

interactions with critical spatial and temporal characteris tic 

is a set-up which allows for simultaneous viewing of both donor 

and acceptor emis sion energy. This is only possible using a device 

which provides a simultaneous split-screen view of the sample. 

These multi-view accessories are mounted to the microscope in 

front of the detector and use filters inte grated into the unit to split 

the donor and acceptor emission fluorescence into two images. 

When FRET viewing is handled this way, the two critical variables— 

time and registra tion—are eliminated. The time of donor and 

acceptor imaging is simultaneous, and given a properly aligned 

unit, the image registra tion is identical, providing a duplicate view 

of the sample. The only difference between the two images is that 

one image is captured with an emission filter for donor emission 

while the other image uses an emission filter for acceptor emission. 

2. Emission Filter Wheels 

When multi-view accessories are not avail able, an automated 

emission filter wheel is the next best alternative. With this configuration, 

a filter cube/holder with a donor excita tion filter and dichroic 

mirror are placed in the microscope. The emission filters for both 

the donor and acceptor fluorophores, in turn, are mounted in the 

emission filter wheel, which can be rapidly switched from one to 

the other. 

Collecting donor and acceptor emission energy using this hardware 

configuration, while not simultaneous, can be accom plished with 

Overview 

FRET, or Forster Resonance Energy Transfer, is a phenomenon 

where closely matched pairs of fluorophores are used 

to determine spatial or temporal proximity and specificity 

in molecular, protein-protein interactions. More specifically, 

this energy transfer occurs when the emission energy of 

one fluorophore—the donor—is non-radiatively transferred 

to the second fluorophore—the acceptor—producing a secondary 

emission. When this occurs, donor fluorescence is 

quenched and acceptor fluorescence increases. 

Biologically, in order for this transfer to occur, the cellular 

conditions need to be such that the distance between 

the molecules being measured is no more than 1-10nm. 

Spectrally, the fluorophores being used need to have a 

large overlap, which while creating the conditions for 

effective energy transfer, also results in spectral bleed 

through (SBT), defined as the overlap of the donor and 

acceptor emission spectra, and can be a problem in FRET 

measurements. 

The development of SBT correction techniques have been 

critical to the evolution of FRET as a useful and more widely 

used application. These SBT correction techniques— 

which include software development, fluorescence 

lifetime imaging (FLIM) correlation, and photo bleaching 

techniques—have reached a degree of sophistication that 

improves the efficacy of FRET. Similarly, the development 

of microscopy techniques such as one-photon, two-photon 

(multi-photon), confocal, and TIRF are all contributing to 

the growing effectiveness and ease of FRET experiments. 

While much has been written about the physical and 

biological aspects of FRET, as summarized above, this 

application note will review the best suited fluorophore 

pairs and summarize the considerations surrounding 

the hardware configuration and selection of optical filters 

required for successful capture, differentiation, and 

measurement of FRET. 

time delays of only 40-75msec (depending on make and model), 

given the state-of-the-art of automated filter wheels as well as 

camera and detector technology. Both temporal changes in the 

sample during live cell imaging and registration shift result ing 

from equipment movement, while almost negated, must still be 

considered when ana lyzing experimental results. 

3. Separate Filter Cubes 

Without a multi-view attachment or emission filter wheel, researchers 

must fall back on a third hardware configuration for FRET, which 

involves using a separate filter cube for both donor and acceptor 

fluorescence. In this con figuration, while each cube has an exciter, 

dichroic and emitter, it is extremely impor tant to remember that the 

exciter and dichroic in both sets are identical and are those filters 

that are typically used with the donor fluorophore. 




89

application note Optimizing Filter Sets for FRET Applications 

While this third filter configuration allows for the discreet collection 

of donor and acceptor fluorescence, it is the configuration most 

susceptible to the time and image registra tion variables mentioned 

previously. The time variable can be minimized as a result of the 

automated turrets, which are a standard feature on many new 

microscopes but may not be typical on older, installed models. In 

addition, alignment of filters within cube tol erances allows more 

room for registration error than in the two other configurations. 

The time and resolution variables that are inherent with this 

configuration must be thoughtfully weighed when using a spatially 

and temporally sensitive technique such as FRET. 

Fluorophore Pairs 

While certain fluorophore pairs such as CFP/YFP, have dominated 

the scientific litera ture and provided the foundation for suc cessful 

FRET studies to date, there has been continued development of 

new monomeric fluorescent proteins such as Midoriishi Cyan and 

Kusabira Orange, for FRET experiments. These fluorophore developments 

have been stimulated by the refine ment of procedures and 

ratio correction techniques, as well as microscopy applica tions that 

are FRET friendly. 

On the most basic level, the success of any given pair of fluorophores 

centers on their spectral characteristics. First, there must be 

sufficient separation of excitation spectra for selective stimulation 

of the donor. Second, there must be sufficient overlap (>30%) 

between the emission spectrum of the donor and the excitation 

spectrum of the acceptor in order to obtain efficient energy transfer. 

And third, there must be sufficient separa tion of the donor and the 

acceptor emission spectra so that the fluorescence of each fluorophore 

can be collected independently. 

Development of new fluorescent proteins has centered on meeting 

these criteria, while producing new colors and fluorophores that 

bind to varied proteins and biological mole cules. The newest 

developments are cited in the links and references to recent 

literature listed below: 

Fluorophore References 

• Wallrabe, H., and Periasamy, A. (2005) FRET-FLIM microscopy 

and spectroscopy in the biomedical sciences. Current Opinion in 

Biotechnology. 16: 19-27. 

• Karasawa, S., Araki, T., Nagai, T., Mizuno, H., Miyawaki, A. (2004) Cyanemitting 

and orange-emitting fluorescent proteins as a donor/acceptor 

pair for fluorescence resonance energy transfer. Biochemical Journal, 

April 5. 

• Shaner, N., Campbell, R., Steinbach, P., Giepmans, B., Palmer, 

A., Tsien, R. (2004) Improved monomeric red, orange, and yellow 

fluorescent proteins derived from Discosoma sp. red fluorescent protein. 

Nature Biotechnology, Vol. 22, Number 12, December. pp.1567-1572. 

Fret Filter Sets 

The products listed in the catalog include the most commonly 

used FRET fluorophore pairs, as well as those recently developed 

pairs that are worthy of attention. For each FRET fluorophore pair 

the chart lists a filter set that is useful in the emission filter wheel 

configuration. These sets are comprised of the exciter and dichroic 

for the donor fluo rophore and emitters for both the donor and 

acceptor fluorophores. 

Individual filter set part numbers for both donor and acceptor 

fluorophores are also listed so components can be purchased 

indi vidually, dependent on the specifics of the hardware set-up. If 

purchasing filters individ ually, it is important to remember that the 

exciter and dichroic from the acceptor fluo rophore set are never 

used. 

It is important that you provide hardware details and related 

mounting instructions when ordering filters for FRET applications. 

Omega Optical 

90 




For multi-color high discrimination applications 

Multiple excitation filters 

Must be mounted in a filter wheel or slider 

QuantaMAX PINKEL FILTERS 

Pinkel interference filter sets offer separate bandpass excitation filters used in conjunction with a multi-band dichroic filter and 

emission filter. This arrangement allows for selective excitation of individual fluorophores using an external filter wheel or slider without 

causing stage vibrations that can affect image quality. Pinkel sets offer improved signal to noise compared to complete multi-band sets, but 

should not be used with a black and white CCD camera. 

Note: to achieve simultaneous multicolor images using a color CCD or the eye as detector, please see our complete multi-band filter sets on 

pages 77 -78. 

QuantaMAX Pinkel Filters 

FITC/TRITC 

or eGFP/DsRed2 

FITC/Texas Red® 

or eGFP/mCherry 

XF452-1 

XF453-1 



2 excitation filters, 1 multi-band dichroic beamsplitter 

and emission filter. 



FITC/ Cy5® XF454-1 2 excitation filters, 1 multi-band dichroic beamsplitter 


DAPI/FITC/Texas Red® 

or DAPI/Spectrum 

Green/Spectrum Red 

XF467-1 



















Dichroic XF2045 400-485-580tbdr 

Emission XF3458 457-528-600tbem 

Pinkel Filters 



Dual Band 

DAPI/FITC 

BFP/eGFP 

FITC/TRITC 

Cy2®/Cy3® 

eGFP/DsRed2 


Excitation #1 XF1006 400DF15 

XF50-1 




XF52-1 Excitation #1 XF1042 485DF15 




FITC/Texas Red® XF53-1 Excitation #1 XF1042 485DF15 




DAPI/TRITC XF59-1 Excitation #1 XF1094 380AF15 







91

standard – PINKEL FILTERS 





Pinkel Filters Continued 



CFP/YFP XF135-1 Excitation #1 XF1079 436DF10 




Triple BanD 



DAPI/Alexa Fluor® 488/546 

DAPI/Cy2®/Cy3® 

DAPI/FITC/TRITC 

DAPI/FITC/Cy3® 


XF63-1 















DAPI/FITC/MitoTracker Red XF69-1 Excitation #1 XF1006 400DF15 





FITC/Cy3®/Cy5® 


FITC/TRITC/Cy5® 





CFP/YFP/DsRed2 XF154-1 Excitation #1 XF1201 436AF8 





Quad BanD 

DAPI/FITC/TRITC/Cy5® 

XF57-1 






Dichroic 

XF2046 

400-485-558- 

640QBDR 

Emission 

XF3059 

460-520-603- 

710QBEM 

92 




For imaging all UV-excited Qdot conjugates 

Sets include a choice of two excitation filters, a single dichroic, 

and emission filters optimized for each Qdot 

Designed to work in all applications using common energy sources 

including broadband arc lamps, LED, lasers and laser diodes 

Standard – QUANTUm dot Filters 

Quantum Dot (QDot) interference filter sets are designed around the center wavelength of each specified Qdot for 

capturing the maximum photon emission with a minimal bandwidth (20nm), thus allowing for multiplexing with other Qdot’s 

without incurring spectral bleed-through. 

Each QDot set can be purchased with one of two excitation filters. The single excitation filter sets are equipped with a 425/45nm filter and 

the two excitation filter sets with a 100nm wide 405nm CWL filter. For most, the single excitation set is suitable as Quantum Dots are typically 

very bright so the wide excitation filter is unnecessary. The two excitation filter sets avoid transmitting potentially harmful UV light in live cell 

applications. 

For a complete list of Quantum Dot filters, please go to page 94. 

Quantum Dot (Qdot) Filters 


For simultaneous 

multi-color viewing to minimize DAPI 


multi-color viewing with 

Xenon excitation 


multi-color viewing with Hg excitation 

100 

XF300 

XF300 

– 

Filter 

actual 

Set 

representation 

for Qdots 





XF02-2 Excitation XF1001 330WB80 



XF05-2 Excitation XF1005 365WB50 



Note: Qdots are naturally bright and therefore do not require high levels of excitation light. 


90 

80 

70 

60 

50 

40 

XF1009 

XF2007 

XF3301 

XF3302 

XF3303 

XF3304 

XF3305 

XF3113 

XF3307 

XF3309 

30 

20 

10 

0 

350 450 550 650 750 850 






93

Standard – QUANTUm dot Filters 





Quantum Dot (Qdot) Filters 




Qdot All Conjugates XF300 Excitation 1 XF1009 425DF45 

Excitation 2 XF1301 415WB100 











Qdot 525 Conjugate 








For single color 


For multiplexing with Qdot 705 

XF301-1 

or 

XF301-2 (Substitute Excitation 2 for Excitation 1) 

XF302-1 

or 


XF303-1 

or 


XF304-1 

or 


XF309-1 

or 


XF305-1 

or 


XF306-1 

or 


XF307-1 

or 


XF308-1 

or 


Excitation 1 XF1009 425DF45 




































94 








Standard – Sedat 

Sedat interference filter sets offer the selectivity of single band filter sets and the microscope stage stability of a multiband 

set. 

Using a multi-band dichroic filter and independent excitation and emission filters mounted in an external slider or wheel, these filter sets 

allow for dye selective excitation and emission collection without requiring vibration-inducing rotation of the filter turret as the dichroic mirror 

is stationary during imaging. 

The use of separate excitation and emission filters will typically offer a higher signal to noise ratio than either a complete multi-band set or 

Pinkel multi-band set. These sets may be used in conjunction with a monochrome CCD camera. 

Note: to achieve simultaneous multicolor images using a color CCD or the eye as detector, please see our full multi-band filter sets on pages 

77-78. 

Sedat Filters 




Dual BanD 

FITC/ TRITC 

Triple BanD 

DAPI/FITC/TRITC 

Quad BanD 

DAPI/FITC/TRITC/Cy5 

DAPI/FITC/TRITC/ 

Alexa Fluor®647 

XF156 

XF157 

XF155 



Dichroic XF2043 490-550DBDRLP 














Excitation 5 XF1208 640AF20 

Dichroic XF2046 400-485-558-640QBDR 









95

Ratio Imaging Filters, IR Blocking, 

IR-DIC and Polarizing Filters 





Interference filter sets for ratiometric imaging applications contain two excitation filters or two emission filters that 

are used in a filter slider or wheel to monitor changes in pH, ion concentration, or other intracellular dynamics. 

Please note: if purchased with a filter cube the multiple excitation or emission filters will be supplied un-mounted unless otherwise instructed. 

Ratio Imaging Filters 


Fluorophores Filter Set SKU Application 

Components 


Single Dye Excitation Sets 

Fura-2, Mag-Fura-2 

PBFI, SBFI 

XF04-2 

UV excited ratiometric set for ion indicator probes. 

Note: some objectives pass 340nm light very poorly. 

BCECF XF16 Dual excitation filter set for ratiometric measurements of 

intracellular ph changes. 




Emission XF3043 510WB40 



Dichroic XF2058 515DRLPXR 


Single Dye Emission Sets 

SNARF®-1 

Widefield 

XF72 

Widefield version of XF31. Filter 610DRLP splits the 

emission signal to 2 detectors. 


Dichroic 1 XF2013 540DCLP 

Dichroic 2 XF2014 610DRLP 



IR Blocking Filters 

Used to reduce infrared energy from the light source in the excitation path (XF83) or in front of the detector in 

the emission path (XF85 and XF86). 

Product SKU Description Application Typical T% Size 

XF83 KG5 Blocks infrared energy at the light source 80% avg. 12, 18, 20, 22, 25, 32, 45, 50, 

50 x 50 mm 

XF85 550CFSP 99+% Near IR Attenuation, 600-1200 nm >75%T 12, 18, 20, 22, 25, 32, 45, 50, 

50 x 50 mm 

XF86 700CFSP 99+% Near IR Attenuation, 750-1100 nm >90%T 

12, 18, 20, 22, 25, 32, 45, 50, 

50 x 50 mm 

IR-DIC Filters 

Used for simultaneous capture of fluorescence and infrared DIC images. 

Product SKU Description Application Size 

XF117 780DF35 Capture of fluorescence and infrared DIC images. 32, 45 mm 

Polarizing Filters 

Used to polarize incident light in both the excitation and emission path. 

Product SKU Description Application Size 

XF120 Polarizing Filter Polarize light in both the excitation and emission path. 10, 12.5, 22, 25, 32, 45, 

50 x 50 mm 


96 







ND Filters, Beamsplitters & Mirrors, 

Multi-Photon and Fluorescence Ref Slide 

Neutral density filters universally attenuate a broad spectral range using either an absorptive or reflective configuration. 

The purpose of these filters is to reduce a transmissive signal to a desired level in a given optical system. Various ND filters 

are available to accommodate individual requirements for signal reduction. 

ND 0.05 = 90% 

ND 0.10 = 80% 

ND 0.20 = 63% 

ND 0.30 = 50% 

ND 0.40 = 40% 

ND 0.50 = 32% 

ND 0.60 = 25% 

ND 0.70 = 20% 

ND 0.80 = 16% 

ND 1.0 = 10% 

ND 2.0 = 1% 

ND 3.0 = 0.1% 

Neutral Density Filters 

For reducing excitation energy. 

(values rounded to the nearest %) 

Sizes: 18Ø 25Ø 32Ø 45Ø 50Ø 50 x 50 

Clear Aperture: 13Ø 20Ø 27Ø 40Ø 45Ø 45 x 45 

Description 

Product SKU 

ND 0.05 XND0.05/18 XND0.05/25 XND0.05/32 XND0.05/45 XND0.05/50 XND0.05/50x50 

ND 0.1* XND0.1/18 XND0.1/25 XND0.1/32 XND0.1/45 XND0.1/50 XND0.1/50x50 











Set of 6 - includes items with* XND6PC/18 XND6PC/25 XND6PC/32 XND6PC/45 XND6PC/50 XND6PC/50x50 

Set of 12 XND12PC/18 XND12PC/25 XND12PC/32 XND12PC/45 XND12PC/50 XND12PC/50x50 

Multi-Photon Filters 


Dichroic XF2033 675DCSPXR 

Laser Blocking Filter XF3100 710ASP 

Multiphoton filters are used in conjunction with two- and three-photon IR laser excitation of fluorophores 

for imaging deeper into samples with minimal photobleaching and photodamage to cells. 

Beamsplitters & Mirrors 

Available in standard dichroic sizes and designed to function at 45 degree angle of incidence from 

400-700nm. 

Product SKU Description Application 

XF121 50/50 Beamsplitter 50%T, 50%R Standard dichroic 



XF125 Reflecting Mirror Opaque backing prevents transmission, ≥ 90% Reflection Standard dichroic 

Extended Reflection Dichroic Only 

XF2031 505DRLPXR FITC Extended Reflection Dichroic 

XF2032 565DRLPXR TRITC Extended Reflection Dichroic 

XF2039 485-555DBDR FITC/TRITC Dual Dichroic with UV Reflection 

Fluorescence Reference Slides 

This set of slides helps to: center and adjust the fluorescence illuminator; verify uniformity of fluorescence 

staining; monitor and adjust laser output and PMT settings; and avoid microspheres and photobleaching. 

Product SKU Set of 4 slides Description 

XF900 Blue emission DAPI/Indo-1/Fura 

Green emission 

FITC/GFP 

Yellow emission 

Acridine Orange 

Red emission 

Rhodamine/Texas Red® 




97

Microscope Filter Holders 

We offer interference filter 

holders for Olympus, Zeiss, Leica, 

and Nikon. This includes holders 

for single dye filter sets, stereo 

microscope holders, and multi 

position sliders. 

Nikon XC106 

Nikon XC104 

Olympus XC111 

Olympus XC113 

Leica XC121 

When purchasing filters and filter holders 

together, you must specify if the filters 

should be installed in the holder. There 

is no extra cost for this service when 

purchased together. 

Please note: if ZPS (zero pixel shift) is 

required, emission filters will be aligned 

and care should be taken to not rotate 

them in the holder. 

Leica XC122 

Leica XC123 

Zeiss XC132 

Zeiss XC136 

Microscope Filter Holders 

Zeiss XC131 

Product SKU Manufacturer & Model Excitation Dichroic Emission 

Nikon 

XC100 Original (Labophot, Diaphot, Optiphot, Microphot, TMD, FXA) 18 mm 18 x 26 mm 18 mm 

XC101 Modified (Labophot, Diaphot, Optiphot, Microphot) 20 mm 18 x 26 mm 22 mm 

XC102 

Quadfluor, Eclipse (E Models; TE 200/300/800; LV 150/150A/100D, Diaphot 200 & 300, 

Labophot 2 and Alphaphot 2) 

25 mm 25.7 x 36 mm 25 mm 

XC104 TE2000, Eclipse 50i, 80i, LV- series 25 mm 25.7 x 36 mm 25 mm 

XC105 

Quadfluor plastic cube, Eclipse (E Models; TE200/300/800; LV 150/150A/100D, Diaphot 

200 & 300, Labophot 2 and Alphaphot 2) 

25 mm 25.7 x 36 mm 25 mm 

XC106 TE2000 plastic cube, compatible with AZ100 25 mm 25.7 x 36 mm 25 mm 

Olympus 

XC110 IMT-2 22 mm 21 x 29 mm 20 mm 

XC111 BH2 (cube style—not barrel, BHT, BHS, BHTU, AHBS 3, AHBT 3) 18 mm 18 x 26 mm 18 mm 

XC113 BX2 (BX, IX, AX) 25 mm 25.7 x 36 mm 25 mm 

XC114 CK-40 (CK Models 31/40/41, CB Models 40/41, CKX 31/41) 20 mm 21 x 29 mm 20 mm 

XC117 BX3 illuminator (BX43, 53, 63) 25 mm 25.7 x 36 mm 25 mm 

Leica 

XC120 

Ploemopak (DMIL, Diaplan, Dialux, Diavert, Fluovert, Labolux, Labovert, Orthoplan, 

Ortholux) 

18 mm 18 x 26 mm 18 mm 

XC121 DM (DML, DMR, DMLB, DMLM, DMLFS, DMLP) 22 mm 21 x 29 mm 22 mm 

XC122 DMIRB (DMIL, DMRXA2, DMLS, DMICHB, DMLSP) 20 mm 18 x 26 mm 20 mm 

XC123 DM2000, DM2500, DM3000, DM4000, DM5000, DM6000 22 mm 21 x 29 mm 22 mm 

XC124 MZ FL III Stereo (Holds 2 emission filters) 18 mm N/A 18 mm 

Zeiss 

XC131 Axio Excitation Slider (for exciters or ND filters, 5 ports) 18 mm N/A N/A 

XC132 Axioskop 2 Cube (Axioplan 2, Axioskop 2, Axiovert 25, Axioskop 2FS) 25 mm 25.7 x 36 mm 25 mm 

XC133 Axiovert 3FL Slider 25 mm 25.7 x 36 mm 25 mm 

XC134 Axioskop 4FL Slider (Axiovert 100/135, Axioplan 1, Axioskop 1, Axioskop FS 1) 25 mm 25.7 x 36 mm 25 mm 


XC136 Axio 2 Push-and-Click 25 mm 25.7 x 36 mm 25 mm 


XC138 Axioskop 8FL Slider 25 mm 25.7 x 36 mm 25 mm 

XC139 Standard 2FL Slider (Axiovert 100/135, Axioplan 1, Axioskop 1, Axioskop FS 1) 25 mm 25.7 x 36 mm 25 mm 

Type 

98 




Optimize Your System 

with the Right Filter Set 


Filter Sets 

A standard epi-fluorescence research microscope is configured to 

hold a number of “filter cubes” (interference filters mounted in a 

microscope’s unique holder) in a rotating turret, or slider, where 

single or multi-color fluorescence imaging is achieved by moving 

one dye-specific filter cube at a time into the light pathway and collecting 

the image information from the sample at the detector, most 

often a scientific grade camera (CCD or CMOS), a PMT, or the eye. 

For successful imaging, the filter cube must be matched to the light 

source, the fluorophore being imaged, and the detector. 

Each filter cube is designed to hold three interference filters, an 

excitation filter, a dichroic mirror, and an emission filter. The excitation 

filter, positioned normal to the incident light, has a bandpass 

design that transmits the wavelengths specific to the fluorophores 

absorption profile. The filtered excitation light reflects off a longpass 

dichroic mirror placed at 45° and excites the fluorophore. The 

mirror has the unique ability to reflect more than 90 percent of the 

light within the reflection band, while passing more than 90% of 

the light in the transmission region. This directs excitation light and 

fluorescence emission appropriately within the optical setup. 

Following excitation, the fluorophore emits radiation at some longer 

wavelength, which passes through the dichroic mirror and emission 

filter to a detector. The emission filter blocks all excitation light 

and transmits the desired fluorescence to produce a quality image 

with high signal-to-noise ratio (Figure 1). 

Interference filters are manufactured to rigorous physical and 

spectral specifications and tolerances. For example, a filter set is 

designed so that the tolerances of the three filters are compatible. 

It is important to note that filters cannot be randomly interchanged 

without the possibility of compromising performance. 

Overview 

The art of fluorescence imaging, requires you to know how 

to make the right interference filter selection. Filter sets are 

designed around a system and an application. The light 

source, fluorophore(s) and detector drive the spectral requirements 

of the filters, and the microscope make and 

model dictate the physical requirements. 

– by Dan Osborn, Fluoresence Microscopy 

Product Manager, Omega Optical 

Choosing a filter set for a fluorescence application can be 

difficult, but armed with knowledge of the microscope, light 

source, detector and fluorophore(s) can make the decision 

easier. The optical properties of filter sets correspond to a 

specific fluorophores excitation and emission spectra. The 

physical dimensions, size and thickness, are tailored to 

specific instrumentation hardware. 

Figure 1 

In a fluorescence filter cube, the incident light passes through the excitation 

filter. The filtered light reflects off a dichroic mirror, striking the fluorophore. The 

longer-wavelength fluorescence emission passes through the dichroic mirror 

and emission filter to the detector. The emission filter blocks stray excitation 

light, providing bright fluorescence against a dark background. 

Filter Set Design 

The goal of every filter set is to achieve an appropriate level of 

contrast (signal over background) for a specific application. First 

and foremost in this regard is to ensure that the weak fluorescence 

emission is separated from the high intensity excitation light. This 

is primarily achieved through the blocking requirements imparted 

on the excitation filter and emission filter. 

Optical density (OD), the degree of blocking, is calculated as -log 

T (transmission). For example, OD 1 = 10 percent transmission, 

OD 2 = 1 percent transmission and OD 3 = 0.1 percent transmission. 

Background “blackness” is controlled by attenuating excitation 

light through the emission filter. The degree of attenuation is 

determined by the total amount of excitation energy passed by the 

emission filter. Interference filters exhibit deep blocking of incoming 

energy at wavelengths near the passband, often achieving 

values of > OD 10 in theory. Therefore, it is this transition from the 

passband to the deep blocking region at the red edge of the excitation 

filter and the blue edge of the emission filter that determines 

much of the contrast enhancing properties of a filter set. The point 

at which the OD curves of the excitation and emission filter overlap 

is called the crossover point. For single band filter sets a crossover 

value of >/= OD 5 is typically specified to achieve a high degree of 

excitation light rejection, reducing the background and increasing 

contrast. Multi band filter sets, because they are most often used 

in visual identification applications, do not require such a degree of 

cross over blocking and values of approximately ≥4 ODs are sufficient 

to ensure good contrast. 

Bandpass filters often consist of the combination of a short-pass 

design, which blocks longer wavelengths and transmits shorter 

ones to approximately 300 - 400nm, and a long-pass design, which 

blocks shorter wavelengths and transmits longer wavelengths. The 

steepness of the transition between the transmission and near- 




99

application note Optimize Your System with the Right Filter Set 

Figure 2 

(%) 

Transmission 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

250 350 450 550 650 750 850 950 1050 

band blocking – important design and performance features – depends 

on the filter design and phase thickness. The phase thickness 

is determined by both the number of interference coating 

layers and their physical thickness. This combination filter design 

can be coated on one surface of a monolithic substrate. Additional 

coating can be applied to the second surface to extend blocking to 

the UV and/or the IR. 

Filter coatings with a high phase thickness produce the steepest 

transition regions, characterized by a ≥1%, five-decade slope factor. 

This means, for a 1% slope factor a 500nm long-pass filter 

Figure 3 


12 

10 

8 

6 

4 

2 

0 

Transmission Scan of Surface Coatings 

providing filter's passband and blocking range 


Side 1 Coating of XF3411 535QM50 


Optical Density Scan of Surface Coatings 

providing filter's passband and blocking range 

250 350 450 550 650 750 850 950 1050 




(the wavelength at 50 percent transmission) will achieve OD5 blocking 

(0.001 percent transmission) at 495nm, or 500nm minus 1 

percent. Less demanding and less expensive designs have fivedecade 

slope factors of 3 to 5 percent. In fluorescence imaging the 

use of steep-edged filter designs is most often exploited where the 

excitation and emission maxima are spectrally very close to each 

other, such as fluorophores with small Stokes shifts. E-GFP, a widely 

used fluorescent protein, has an excitation absorption maximum at 

488nm and an emission maximum at 509nm. With a Stokes shift 

of only 21nm it becomes imperative that the filters used to separate 

out the excitation source light from the fluorescence emission 

achieve a very high level of blocking in a short spectral distance. 

If the excitation and emission filter edges are not very steep they 

should be placed spectrally further apart to gain deep blocking. 

This will reduce the filters ability to deliver and capture photons at 

the fluorophores absorption and emission maximums. 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Figure 4 

QMAX Filter Set XF404 overlaid on eGFP EX and EM Curves 

350 400 450 500 550 600 650 700 


XF1416 470QM40 

XF3411 535QM50 


eGFP Excitation 

eGFP Emission 

System-Based Needs 

Epi-fluorescence systems are the most common in fluorescence 

microscopy. Standard filter sets have transmission and blocking 

optimized for the application’s fluorophore(s) and the white light 

used for excitation, usually a mercury arc or xenon arc lamp. 

The mercury arc lamp is most commonly used because of its 

brightness. Its five energy peaks, 365, 405, 436, 546 and 577 nm, 

affect application performance and are considered in the filter set 

designs. The xenon lamp, though not as bright, irradiates uniformly 

between 300 and 800 nm with energy peaks beginning at ~820 

nm. This is recommended for ratio imaging. 

The Nipkow disc scanning confocal microscope contains optics similar 

to those in the epi-fluorescence system and therefore requires 

similar filters. However, laser scanning confocal microscopes require 

filters designed for the specific laser used for excitation. The 

secondary lines and other unwanted background signals caused 

by the lasers demand customized excitation filters. Emission filters 

must have greater than OD5 blocking and antireflection coatings on 

both sides to minimize skew rays reflecting off secondary surfaces. 

As in epi-fluorescence systems, dichroic mirrors must efficiently 

reflect specific laser wavelengths and transmit the desired fluorescence. 

Multiphoton microscopy, another laser-based fluorescence 

technique, requires a tunable pulsed Ti:sapphire infrared laser. 

This light source excites shorter-wavelength fluorophores, contrary 

to conventional fluorescence systems. 

100 




At the focal point, a fluorophore absorbs two photons simultaneously. 

The combined energy elevates the fluorophores electrons 

to a higher energy level, causing it to emit a photon of lower energy 

when the electrons return to the ground state. For example, 

a 900nm laser pulse will excite at 450nm and yield fluorescence 

emission at ~500nm, depending on the fluorophore. This technique 

generally uses a combination of a shortpass dichroic mirror 

and an emission filter with deep blocking at the laser line. An allpurpose 

multiphoton short-pass dichroic mirror reflects radiation 

between 700 and 1000nm — the range of Ti:sapphire lasers — 

and transmits visible light. The emission filter must transmit fluorescence 

and block the laser light to more than OD6. 

Application Relevance 

A number of applications have been developed around epi-fluorescence 

in the research laboratory, and some are being extended to 

confocal and multiphoton. Example, ratio imaging can be used to 

quantify environmental parameters such as calcium-ion concentration, 

pH and molecular interactions, and it demands a unique 

set of filters. For example, Fura-2, a calcium dependent fluorophore, 

has excitation peaks at 340 and 380nm requiring excitation 

filters that coincide with the peaks and a dichroic mirror that 

reflects them. The xenon arc lamp is an ideal excitation source for 

epifluorescence because of its uniform intensity over the excitation 

range. A mercury arc source may require additional balancing filters 

to attenuate the effects of the energy peaks. 

In fluorescence resonance energy transfer (FRET), energy is transferred 

via dipole-dipole interaction from a donor fluorophore to a 

nearby acceptor fluorophore. The donor emission and acceptor excitation 

must spectrally overlap for the transfer to happen. A standard 

FRET filter set consists of a donor excitation filter, a dichroic 

mirror and an acceptor emission filter. Separate filter sets for the 

donor and acceptor are recommended to verify dye presence, but 

most importantly, single-dye controls are needed because donor 

bleed-through into the acceptor emission filter is unavoidable. 

Recently, fluorescence detection has found an expanded role in 

the clinical laboratory as well. Tests for the presence of the malaria 

causing parasite, Plasmodium, are traditionally performed using 

a thin film blood stain and observed under the microscope. Although 

an experienced histologist can identify the specific species 

of Plasmodium given a quality stained slide, the need for rapid field 

identification of potential pathogens is not met using this method, 

particularly in resource poor third world countries. The use of the 

nucleic acid binding dye Acridine Orange together with a simple 

portable fluorescence microscope, equipped with the proper filter 

set, can significantly reduce assay time and provide a more sensitive 

detection method. 

In another test using fluorophore tagged PNA (peptide nucleic 

acids) as ribosomal RNA (rRNA) probes specific for pathogenic 

yeasts and bacterium’s such as C. albicans and S. aureus, clinicians 

can make accurate positive or negative determinations in 

fewer than two hours. The sensitivity and reduced processing time 

of the assay greatly enhances positive patient outcomes compared 

to previously used cell culture methods. 

In both techniques, the filters must provide specific excitation light 

to the sample in order to generate the required fluorescence, and 

more importantly, reproducibly provide the desired signal level and 

color rendition to allow for accurate scoring. For this to occur, the 

filter manufacturer must apply stringent tolerances to each component 

in the filter set to ensure its proper functioning in the clinical 

laboratory. 

Figure 5 

Using fluorescence detection as 

a visual test for determining the 

presence of pathogenic organisms 

requires precise band placement 

for accurate color determinations. 

Photo courtesy Advandx Corp. 

Multicolor imaging is extending to 800nm and beyond, with farred 

fluorophores readily available and CCD camera quantum efficiencies 

being pushed to 1200 nm. There are a multitude of filter 

combinations from which to choose, depending on the application, 

each with its own advantages and disadvantages. A standard multi-band 

filter set allows simultaneous color detection by eye and is 

designed for conventional fluorophores such as DAPI (blue), fluorescein 

(green) and rhodamine/Texas red (orange/red). Two and 

three-color sets are most common, while the fourth color in a fourcolor 

set includes a fluorophore in the 650 to 800nm range. Multiple 

passbands limit the deep blocking achieved in single-band 

filter sets, resulting in a lower signal-to noise ratio from multi-band 

sets. 

For an increased signal-to-noise ratio and better fluorophore-tofluorophore 

discrimination, Pinkel filter sets for the camera consist 

of single- and multi-band filters. For microscopes that are equipped 

with an excitation slider or filter wheel, changing single-band excitation 

filters allows single-color imaging of multi-labeled samples. 

The Pinkel filter holder and sample slide remain fixed, minimizing 

registration errors. 

A Sedat set hybrid combines a similar suite of single-band excitation 

filters in a filter wheel; a set of single-band emission filters, 

along with an emission filter slider or wheel; and a multi-band dichroic 

housed in a filter holder. Such a hybrid setup will increase 

the signal-to-noise ratio and discrimination even more than a traditional 

Pinkel set. The disadvantages of Pinkel and Sedat sets to 




101

Optimize Your System 

with the Right Filter Set 

application note Optimize Your System with the Right Filter Set 

multi-band sets include increased filter cost and the inability to 

image multiple colors simultaneously. Instead, commercially available 

imaging software can be used to merge separate images. 

Fluorescence in situ hybridization (FISH) applications attempt to 

image as many colors as possible in a single sample. For example, 

multiple fluorescent labeled DNA probes can identify genes colorimetrically 

on a single chromosome. Optimized signal-to-noise ratio 

and color discrimination require narrowband single- dye filter sets. 

The filters must conform to tighter spectral tolerances than standard 

bandpass filter sets to minimize excitation/emission overlap 

of spectrally close fluorophores. Minor passband edge shifts may 

significantly compromise fluorophore discrimination. In addition, 

these narrowband filters must be optimized for transmission to provide 

adequate signal. 

Choosing optical filter sets for fluorescence microscopy can be 

confusing. Proper bandwidths, degree and extent of blocking, and 

80 

the type of filter design for your application are important considerations. 

We can help with your decision-making. Please feel free to 

contact us for assistance. 

70 

100 

90 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

450 500 550 600 650 700 750 


XF 

XF 

XF 

Sp 

Ex 

Sp 

Em 

60 

50 

40 

30 

20 

Figure 6 

Filter sets used in mFISH assays exhibit narrow 

filter bandwidths for minimizing spectral 

bleedthrough of non-specfic fluorophores and 

accurate color reperesentation. Reperesented 

here is Omega filter set XF424 for Spectrum Red, 

Texas Red, and similar fluors. 

XF1424 580QM30 

XF3418 630QM36 


Spectrum Red 

Excitation 

Spectrum Red 

Emission 

10 

0 

450 500 550 600 650 700 750 

102 




choosing the optimal filter set 

Please consult our Fluorophore Reference Table (pages 105-107) for excitation and emission peaks, as well as for recommended filter 

sets, or visit curvomatic on our website. 

What is most important in your application – bright signal, dark background, color discrimination, or high signal-to-noise? While no 

single design can optimize for all dimensions, many designs provide a solution that gives good overall performance. 

• Does your application require customized reflection and transmission specifications for your dichroic? 

Call us for assistance. 

• Does your application require “imaging quality” filters? All 3 rd Millennium and QuantaMAX fluorescence filters in this catalog 

are suitable for imaging applications. 

What is your light source – halogen, laser, LED, mercury, xenon? Filters are designed to optimize performance for different light sources. 

Specify your detector – CCD, PMT, CMOS, film, eye. Filter blocking strategies are designed to optimize performance for different detectors. 

Zero Pixel Shift 

ZPS is recommended for multi-color applications and results in better discrimination. ZPS is also recommended for applications such as 

FISH (fluorescence in-situ hybridization), CGH (comparative genomic hybridization), SKY (spectral karyotyping), and co-localization studies. 

Please specify when ZPS is required. An additional charge may be added to the price of some sets. 

Figure of Merit - NEW Feature on Curvomatic 

Our new Figure of Merit calculator allows you to obtain the relative 

value of a single filter set effectiveness when combined with a light 

source and a single fluorophore to capture the spectral absorption 

and emission probability curves. 

When considering the merit of two or more filter sets independently, 

against the same fluorophore, the set with higher value will offer a 

greater ability to capture the fluorescence signal. The number returned 

by the Figure of Merit is a single benchmark by which to gauge if your 

filter set selection is best for a given application, or to compare two 

or more sets effectiveness against a particular fluorophore. It does 

not give a measure of the relative brightness that will be seen in the 

microscope as it does not consider the quantum yield or absorption 

coefficients of the selected fluorophore, the sample labeling density, 

or other experimental variables. Factors such as detector sensitivity 

at a given wavelength, the presence of other fluorophores, slight 

shifts in the absorption or emission peaks of the fluorophore, and the 

sample background all contribute to the overall system efficiency and 

are not considered here. 

Understanding the Results 

A few examples of returned results can help demonstrate how the 

Figure of Merit can help you decide which filter set is optimal in your 

set of conditions. 

Q: The results of filter set “X” and fluorophore “Y” = 0. 

Why the results are zero: 

A: The filter set is incompatible with the fluorophore or the light 

source (if selected). 

Check to make sure the fluorophores absorbance and emission 

profiles overlap the filter set's excitation and emission passbands. 

Verify that the excitation filter transmits the light source efficiently. 

Q: The results of filter set “X” and fluorophore “Y” is 425. 

Using the same fluorophore (“Y”) with a different filter set 

(“Z”) the result is 577. Is filter set “Z” the one I want? 

A: Figure of Merit is but one benchmark to use in making this decision. 

If filter set “Z” contains a long pass emission filter it will collect more 

signal (if the excitation filter is equivalent) than a bandpass filter and 

return a higher number, but it may also collect more background 

photons or signal from other fluorophores in the sample. If sample 

background and spectral bleed-through are not issues, then Set “Z” 

is the best choice. 

Q: I compared a narrow band filter (mFISH set XF202) to 

a wider band set (XF404 for Cy 2) and the returned values 

were 130.5 and 535.1 respectively. I am doing a multicolor 

assay and am worried about spectral bleed-through. Is 

the value too low for this set to be useful? 

A: No. A number that comes in several fold lower than another set, 

using the same fluorophore and light source, may indicate that in 

an ideal situation the higher value set will provide a much stronger 

signal, but it does not account for any noise factors. If you are doing 

a multicolor assay and do not efficiently reject bleed-through from 

other fluorophores, you may increase the total signal using the higher 

scoring filter set , but reduce the signal-to-noise because of the 

spectral bleed-through. You can actually use the tool to estimate the 

spectral bleed-through by placing another fluorophore on the graph 

and seeing the returned value of the two filter sets. In this case, if 

the other fluorophore was Cy3, the returned values for the XF202 and 

XF404 are 1.8 and 18.6 respectively. 




103

Typical Epi-fluorescence Configuration 

Successful fluorescence imaging requires three filters mounted as a single unit in a filter cube or holder, secured 

in a fluorescence microscope with the proper lightsource and detector. The excitation filter, positioned normal to the incident 

light, has a bandpass design that transmits the wavelengths. The filtered excitation light reflects off a long-pass dichroic mirror 

placed at 45° and excites the fluorophore. The mirror has the unique ability to reflect more than 90 percent of the light within 

the reflection band while passing more than 90 percent of the light in the transmission region. This directs excitation light and 

fluorescence emission appropriately within the optical setup. 

Following excitation, the fluorophore emits radiation at some longer wavelength, which passes through the dichroic mirror and emission filter 

into a detector. The emission filter blocks all excitation light and transmits the desired fluorescence to produce a quality image with high 

signal-to-noise ratio (See below). 

Emission Filter 

Detector 

Light Source 

Dichroic Mirror 

Excitation Filter 

Light Path Excitation 

Light Path Emission 

Sample 

In a fluorescence filter cube, the incident light passes through the excitation filter. The filtered light reflects off a dichroic mirror, 

striking the fluorophore. The longer-wavelength fluorescence emission passes through the dichroic mirror and emission filter to 

the detector. The emission filter blocks stray excitation light, providing bright fluorescence against a dark background. 

104 




FLUOROPHORE REFERENCE CHART 

Fluorophores 

(A-B) 

Fluorophores 

(B-C) 

Fluorophore EX EM Best Set Page # Fluorophore EX EM Best Set Page # 

AcGFP1 475 505 XF404 72 BODIPY® 505/515 502 510 XF404 72 

Acridine Yellow 470 550 XF23 74 BODIPY® 530/550 533 550 XF402 72 

Acridine orange (+DNA) 500 526 XF412 72 BODIPY® 558/568 558 568 XF402 72 

Acridine orange (+RNA) 460 650 XF403 72 BODIPY® 564/570 564 570 XF402 72 

Alexa Fluor® 350 347 442 XF403 72 BODIPY® 581/591 582 590 XF414 72 

Alexa Fluor® 405 401 421 Visit website BODIPY® 630/650-X 630 650 XF45 76 

Alexa Fluor® 430 434 540 XF14-2 73 BODIPY® 650/665-X 650 665 XF416 72 

Alexa Fluor® 488 495 519 XF404 72 BODIPY® 665/676 665 676 XF416 72 

Alexa Fluor® 500 503 525 XF412 72 BTC 401/464 529 Visit website 

Alexa Fluor® 532 531 554 XF412 72 Calcein 494 517 XF404 72 

Alexa Fluor® 546 556 573 XF402 72 Calcein Blue 375 420 XF408 72 

Alexa Fluor® 555 553 568 XF402 72 Calcium Crimson 590 615 XF414 72 

Alexa Fluor® 568 579 604 XF414 72 Calcium Green-1 506 531 XF412 72 

Alexa Fluor® 594 591 618 XF414 72 Calcium Orange 549 576 XF402 72 

Alexa Fluor® 610 612 628 XF414 72 Calcofluor® White 350 440 XF408 72 

Alexa Fluor® 633 632 647 XF140-2 75 5-Carboxyfluorescein (5-FAM) 492 518 XF404 72 

Alexa Fluor® 647 653 669 XF110-2 75 5-Carboxynaphthofluorescein (5-CNF) 598 668 XF414 72 

Alexa Fluor® 660 663 690 XF141-2 75 6-Carboxyrhodamine 6G 525 555 XF412 72 

Alexa Fluor® 680 679 702 XF141-2 75 5-Carboxytetramethylrhodamine (5-TAMRA) 522 576 XF402 72 

Alexa Fluor® 700 702 723 XF142-2 75 Carboxy-X-rhodamine (5-ROX) 574 602 XF414 72 

Alexa Fluor® 750 749 775 Visit website Cascade Blue® 400 420 XF408 72 

Alexa Fluor® 488/546 FRET 495 573 XF164 88 Cascade Yellow 402 545 XF106 73 

Alexa Fluor® 488/555 FRET 495 568 XF164 88 GeneBLAzer (CCF2) 402 520 XF106 73 

Alexa Fluor® 488/Cy3® FRET 495 570 XF165 88 Cell Tracker Blue 353 466 XF408 72 

Allophycocyanin (APC) 650 660 XF416 72 Cerulean 433 475 XF401 72 

AMCA/AMCA-X 345 445 XF408 72 CFP (Cyan Fluorescent Protein) 434 477 XF412 72 

AmCyan1 458 489 Visit website CFP/DsRed2 FRET 434 583 XF152 88 

7-Aminoactinomycin D (7-AAD) 546 647 XF103-2 74 CFP/YFP FRET 434 527 XF88 88 

7-Amino-4-methylcoumarin 351 430 XF408 72 Chromomycin A3 450 470 XF114-2 73 

Aniline Blue 370 509 XF09 76 Cl-NERF (low pH) 504 540 XF104-2 74 

ANS 372 455 XF05-2 73 CoralHue Azami Green 492 505 Visit website 

AsRed2 578 592 XF405 72 CoralHue Dronpa Green 503 518 CALL — 

ATTO-TAG CBQCA 465 560 XF18-2 73 CoralHue Kaede Green 508 518 Visit website 

ATTO-TAG FQ 486 591 XF409 72 CoralHue Kaede Red 572 580 Visit website 

Auramine O-Feulgen 460 550 Visit website CoralHue Keima Red 440 620 CALL — 

Azami Green 493 505 XF404 72 CoralHue Kusabira Orange (mKO) 552 559 XF402 72 

BCECF 503 528 XF16 96 CoralHue Midoriishi-Cyan (MiCy) 472 492 XF410 72 

BFP (Blue Fluorescent Protein) 382 448 XF403 72 CPM 385 471 Visit website 

BFP/DsRed2 FRET 382 583 XF159 88 6-CR 6G 518 543 XF412 72 

BFP/eGFP FRET 382 508 XF89-2 88 CryptoLight CF-2 584/642 657 Visit website 

BFP/YFP FRET 382 527 XF158 88 CryptoLight CF-5 566 597 Visit website 

BOBO-1, BO-PRO-1 462 481 XF401 72 CryptoLight CF-6 566 615 XF414 72 

BOBO-3, BO-PRO-3 570 604 XF414 72 CTC Formazan 450 630 XF21 76 

BODIPY® FL - Ceramide 505 513 XF404 72 Cy2® 489 506 XF404 72 

BODIPY® TMR 542 574 XF402 72 Cy3® 550 570 XF402 72 

BODIPY® TR-X 589 617 XF414 72 Cy3.5® 581 596 XF414 72 

BODIPY® 492/515 490 515 XF404 72 Cy5® 649 670 XF407 72 

BODIPY® 493/ 503 500 506 XF404 72 Cy5.5® 675 694 XF141-2 75 

BODIPY® 500/ 510 509 515 XF412 72 Cy7® 743 767 Visit website 




105

FLUOROPHORE REFERENCE CHART 

Fluorophores 

(C-G) 

Fluorophores 

(G-M) 


Cy3®/Cy5.5® FRET 550 694 XF167 88 eGFP/Rhod-2 FRET 488 571 XF151-2 88 

Cy Pet 435 477 XF401 72 HcRed 591 613 XF414 72 

Cycle 3 GFP 395/478 507 XF76 76 HiLyte Fluor 488 497 525 XF401 72 

Dansyl cadaverine 335 518 XF02-2 73 HiLyte Fluor 555 550 566 XF402 72 

Dansylchloride 380 475 Visit website HiLyte Fluor 647 649 672 XF140-2 75 

DAPI 358 461 XF403 72 HiLyte Fluor 680 688 700 XF141-2 75 

Dapoxyl® 373 574 XF05-2 73 HiLyte Fluor 750 750 782 Visit website 

DiA (4-Di-16-ASP) 491 613 XF21 76 Hoechst 33342 & 33258 352 461 XF403 72 

DiD (DilC18(5)) 644 665 XF416 72 7-Hydroxy-4-methylcoumarin (pH 9) 360 449 XF408 72 

DIDS 341 414 XF408 72 1,5 IAEDANS 336 482 XF02-2 73 

DiL (DiLC18(3)) 549 565 XF405 72 Indo-1 330 401 Visit website 

DiO (DiOC18(3)) 484 501 XF404 72 ICG (Indocyanine Green) 785/805 835 XF148 75 

DiR (DiIC18(7)) 750 779 Visit website JC-1 498/593 525/595 XF409 72 

Di-4 ANEPPS 488 605 XF21 76 6-JOE 525 555 XF412 72 

Di-8 ANEPPS 468 635 XF21 76 JOJO-1, JO-PRO-1 529 545 XF412 72 

DM-NERF (4.5–6.5 pH) 510 536 XF412 72 JRed 584 610 XF406 72 

DsRed2 (Red Fluorescent Protein) 558 583 XF405 72 Keima Red 440 620 Visit website 

DsRed-Express 557 579 XF405 72 Kusabira Orange 548 559 XF405 72 

DsRed Monomer 556 586 XF405 72 Lissamine rhodamine B 570 590 XF414 72 

ELF® -97 alcohol 345 530 XF09 76 LOLO-1, LO-PRO-1 565 579 Visit website 

Emerald 487 509 XF404 72 Lucifer Yellow 428 536 XF14-2 73 

EmGFP 487 509 XF404 72 LysoSensor Blue (pH 5) 374 424 XF131 73 

Eosin 524 544 XF404 72 LysoSensor Green (pH 5) 442 505 XF404 72 

Erythrosin 529 554 XF104-2 74 LysoSensor Yellow/Blue (pH 4.2) 384 540 Visit website 

Ethidium bromide 518 605 XF103-2 74 LysoTracker® Green 504 511 XF412 72 

Ethidium homodimer-1 (EthD-1) 528 617 XF103-2 74 LysoTracker® Red 577 592 XF406 72 

Europium (III) Chloride 337 613 XF02-2 73 LysoTracker® Yellow 465 535 XF18-2 73 

5-FAM (5-Carboxyfluorescein) 492 518 XF404 72 Mag-Fura-2 330 491 XF04-2 96 

Fast Blue 365 420 XF408 72 Mag-Indo-1 330 417 Visit website 

Fluorescein (FITC) 494 518 XF404 72 Magnesium Green 506 531 XF412 72 

FITC/Cy3® FRET 494 570 XF162 88 Marina Blue® 365 460 XF408 72 

FITC/Rhod 2 FRET 494 571 XF162 88 mBanana 540 553 CALL — 

FITC/TRITC FRET 494 580 XF163 88 mCherry 587 610 XF406 72 

Fluo-3 506 526 XF412 72 mCitrine 516 529 XF412 72 

Fluo-4 494 516 XF404 72 4-Methylumbelliferone 360 449 XF408 72 

FluorX® 494 519 XF404 72 mHoneydew 487 537 CALL — 

Fluoro-Gold (high pH) 368 565 XF09 76 Midorishii Cyan 472 495 XF410 72 

Fluoro-Gold (low pH) 323 408 XF05-2 73 Mithramycin 395 535 XF14-2 73 

Fluoro-Jade 475 525 XF404 72 Mitofluor Far Red 680 650-773 XF142-2 75 

FM® 1-43 479 598 XF409 72 Mitofluor Green 490 516 XF404 72 

Fura-2 335 505 XF04-2 96 Mitofluor Red 589 588 622 XF414 72 

Fura-2/BCECF 335/503 505/528 Visit website Mitofluor Red 594 598 630 XF414 72 

Fura Red 436 637 Visit website MitoTracker® Green 490 516 XF404 72 

Fura Red/Fluo-3 472/506 672/527 Visit website MitoTracker® Orange 551 576 XF402 72 

GeneBLAzer (CCF2) 402 520 Visit website MitoTracker® Red 578 599 XF414 72 

GFP wt 395/ 475 509 Visit website MitoTracker® Deep Red 644 655 XF416 72 

eGFP 488 508 XF404 72 mOrange 548 562 XF402 72 

GFP (sapphire) 395 508 XF76 76 mPlum 590 649 XF416 72 

eGFP/DsRed FRET 470 585 XF151-2 88 mRaspberry 598 625 XF414 72 

mRFP 584 607 XF407 72 

106 




Fluorophores 

(M-S) 

Fluorophores 

(S-Z) 


mStrawberry 574 596 Visit website Sodium Green 507 535 XF412 72 

mTangerine 568 585 XF402 72 SpectrumAqua® 433 480 XF201 80 

mTFP 462 492 Visit website SpectrumBlue® 400 450 XF408 72 

NBD 465 535 XF18-2 73 SpectrumGold® 530 555 XF203 80 

Nile Red 549 628 XF103-2 74 SpectrumGreen® 497 524 XF202 80 

Oregon Green® 488 496 524 XF404 72 SpectrumOrange® 559 588 XF204 80 

Oregon Green® 500 503 522 XF412 72 SpectrumRed® 587 612 XF207 80 

Oregon Green® 514 511 530 XF412 72 SpectrumFRed® 655 675 XF208 80 

Pacific Blue 410 455 XF119-2 73 SYTO® 11 508 527 XF412 72 

PBF1 334 504 XF04-2 96 SYTO® 13 488 509 XF404 72 

C-phycocyanin 620 648 XF45 76 SYTO® 17 621 634 Visit website 

R-phycocyanin 618 642 XF414 72 SYTO® 45 452 484 XF401 72 

R-phycoerythrin (PE) 565 575 XF402 72 SYTOX® Blue 445 470 XF401 72 

Phi YFP 525 537 XF412 72 SYTOX® Green 504 523 XF412 72 

PKH26 551 567 XF402 72 SYTOX® Orange 547 570 XF402 72 

POPO-1, PO-PRO-1 434 456 XF401 72 5-TAMRA (5-Carboxytetramethylrhodamine) 542 568 XF402 72 

POPO-3, PO-PRO-3 534 572 XF402 72 tdTomato 554 581 XF173 74 

Propidium Iodide (PI) 536 617 XF103-2 74 Tetramethylrhodamine (TRITC) 555 580 XF402 72 

PyMPO 415 570 Visit website Texas Red®/Texas Red®-X 595 615 XF414 72 

Pyrene 345 378 XF02-2 73 Thiadicarbocyanine 651 671 XF47 76 

Pyronin Y 555 580 XF402 72 Thiazine Red R 510 580 Visit website 

Qdot 525 Conjugate UV 525 XF301-1 93 Thiazole Orange 453 480 XF401 72 

Qdot 565 Conjugate UV 565 XF302-1 93 Topaz 514 527 XF412 72 

Qdot 585 Conjugate UV 585 XF303-1 93 T-Sapphire 399 511 XF76 76 

Qdot 605 Conjugate UV 605 XF304-1 93 TOTO®-1, TO-PRO®-1 514 533 XF412 72 

Qdot 625 Conjugate UV 625 Visit website TOTO®-3, TO-PRO®-3 642 660 XF416 72 

Qdot 655 Conjugate UV 655 XF305-1 93 TO-PRO®-5 748 768 Visit website 

Qdot 705 Conjugate UV 705 XF306-1 93 Turbo RFP 553 574 XF402 72 

Qdot 800 Conjugate UV 800 Visit website Turbo YFP 525 538 XF412 72 

Quinacrine Mustard 423 503 XF14-2 73 Venus 515 528 XF412 72 

Resorufin 570 585 XF414 72 WW 781 605 639 XF45 76 

Red Fluorescent Protein (DsRed2) 561 585 XF402 72 X-Rhodamine (XRITC) 580 605 XF414 72 

RH 414 500 635 XF103-2 74 YFP (Yellow Fluorescent Protein) 513 527 XF412 72 

Rhod-2 550 571 XF402 72 YFP/Cy3® FRET 513 570 XF167 88 

Rhodamine B 555 580 XF402 72 YFP/TRITC FRET 513 580 XF166 88 

Rhodamine Green 502 527 XF412 72 YOYO®-1, YO-PRO®-1 491 509 XF404 72 

Rhodamine Red 570 590 XF414 72 YOYO®-3, YO-PRO®-3 612 631 XF414 72 

Rhodamine Phalloidin 542 565 XF402 72 Ypet 517 530 XF412 72 

Rhodamine 110 496 520 XF404 72 ZsGreen1 493 505 XF404 72 

Rhodamine 123 507 529 XF412 72 ZsYellow1 529 539 XF412 72 

5-ROX (carboxy-X-rhodamine) 574 602 XF414 72 

SBFI 334 525 XF04-2 96 

SensiLight P-1 550 664 Visit website 

SensiLight P-3 609 661 XF45 76 

Sirius 360 420 XF149 73 

SITS 337 436 XF408 72 

SNAFL®-1 576 635 Visit website 

SNAFL®-2 525 546 Visit website 

SNARF®-1 575 635 XF72 96 




107

Emission Color Chart 

Emission Color Chart 

excitation 

emission 

350 400 450 500 550 600 650 700 750 

Dual BanD 

XF50 

XF135 

XF52 

XF53 

XF92 

Triple BanD 

XF63 

XF56 

XF67 

XF66 

XF68 

XF69 

XF93 

Quad BanD 

XF57 

350 400 450 500 550 600 650 700 750 

108 




Light Source and detector reference charts 

Lasers 

Detectors 

Helium-neon 543 594 633 

10 0 

200nm 300 400 500 600 700 

Argon/Krypton 346 351 457 476 488 514 647 676 

10 -2 

200nm 300 400 500 600 700 

Argon Ion 346 351 457 476 488 514 

200nm 300 400 500 600 700 

Arc Lamps 

10 -1 350nm 450 550 650 750 

Relative spectral response of 

the commonly used detectors: 

photopic human eye, scotopic 

human eye and color film. 

100 

0 

yellow Dye 

Scotopic Eye Response 

Magenta Dye 

Photopic Eye Response 

Cyan Dye 

Mercury 313 334 365 405 436 546 577 

10 -2 

50 

10 -1 

0 

350nm 450 550 650 750 

200nm 300 400 500 600 700 

Xenon 

Normalized response of bi-alkali 

PMT detector, extended red PMT 

detector, silicon detector, S20 PMT 

and CCD. 

LED 

Bi-alkali PMT 

S20 PMT 

Extended Red PMT 

CCD 

Si Photodiode 

200nm 300 400 500 600 700 800 900 1000 1100 

Exfo 

Metal Halide 

300nm 400 500 600 700 800 900 

LAMs spectrum fluorophore 

Normalised 

precisExcite LED options 

DAPI GFP Alexa594 

Hoechst FITC mCherry 

Alexa488 Red 

Pacific Blue Texas 

CFP 

Cy3.5 

YFP 

Cy3 

Cy5 

TRITC 

mRFP 

375 400 425 450 475 500 525 550 575 600 625 650 675 

400 

445 

490 525 565 595 635 

244-3403 

244-3406 

244-3413 244-3401 

244-3411 244-3407 

244-3408 

465 

244-3402 

505 

244-3405 

535 

244-3410 

585 

244-3412 




109

glossary 

A 

B 

C 

Angle of Incidence (AOI): The angle formed by an 

incident ray of light and an imaginary line perpendicular to 

the plane of the component’s surface. When the ray is said 

to be “normal” to the surface, the angle is 0°. 

Anti-Reflective Coating (AR): An optical thin-film 

interference coating designed to minimize reflection that 

occurs when light travels from one medium into another, 

typically air and glass. 

Bandpass: The range (or band) of wavelengths passed by 

a wavelength-selective optic. 

Bandpass Filter: Transmits a band of color, the center 

of which is the center wavelength (CWL). The width of 

the band is indicated by the full width at half maximum 

transmission (FWHM), also known as the half band width 

(HBW). It attenuates the light of wavelengths both longer 

and shorter than the passband. 

Bandwidth (HBW, FWHM): Width of the passband: 

specifically, the difference between the two wavelengths at 

which the transmittance is half the peak value. 

Blocking: Attenuation of light, usually accomplished by 

reflection or absorption, outside the passband. Blocking 

requirements are specified by wavelength range and 

amount of attenuation. 

Broadband AR Coating: A coating designed to reduce 

reflectance over a very wide (broad) band of wavelengths. 

Cavity: Sometimes called “period”. The basic component 

of a thin-film filter consists of two quarter-wave stack 

reflectors separated by a solid dielectric spacer. As the 

reflectivity of each of the quarter wave stack reflectors 

increases, the FWHM decreases; as the number of cavities 

increases, the depth of the blocking outside the passband 

increases and the shape of the passband becomes 

increasingly rectangular. 

Center Wavelength (CWL): The arithmetic center of the 

passband of a bandpass filter. It is not necessarily the same 

as the peak wavelength. 

Clear Aperture (CA): The central, useable area of a filter 

through which radiation can be transmitted. 

D 

E 

F 

H 

Cut-on or Cut-off Slope: A measure of the steepness 

of the transmittance curve x 100% where λ 80% 

and λ 5% 

correspond to 80% and 5% to absolute transmittance 

points. 

Cut-on or Cut-off Wavelength (λ C 

): The cut-on is the 

wavelength of transition from attenuation to transmission, 

along a continuum of increasing wavelength. The cut-off is 

the wavelength of transition from transmission to reflection. 

The cut-on is the wavelength of transition from attenuation 

to transmission generally specified as the point at which the 

transition slope achieves 50% of peak transmission. The 

cut-off is the wavelength of transition from transmission to 

attenuation and again specified as the 50% point of peak 

transmission. 

Dual Magnetron Reactive Sputtering: A thin film 

coating method utilizing an energetic plasma in a controlled 

magnetic field and vacuum environment to precisely 

deposit alternating layers of high and low refractive index 

materials yielding a desired spectral response. 

Evaporated Coating: Precisely controlled thin layers of 

solid material(s) deposited on a substrate after vaporization 

under high-vacuum conditions. 

Fabry-Perot Etalon: A non-absorbing, multi reflecting 

device, similar in design to the Fabry-Perot interferometer, 

which serves as a multilayer, narrow bandpass filter. 

Half Bandwidth (HBW): The wavelength interval of the 

passband measured at the half power points (50% of peak 

transmittance). Expressed as half bandwidth (HBW), full 

width half maximum (FWHM) or half power bandwidth 

(HPBW). 

110 




I 

R 

O 

P 

Q 

Intensity Crosstalk: Intensity crosstalk occurs between 

channels and is a result of non-ideal optical filtering, where 

light from neighboring channels can leak through and be 

detected along with the filtered signal of interest. When the 

leakage level of a neighboring channel is higher than the 

noise floor that is associated with the channel of interest, it 

becomes the dominant noise factor in the SNR. As a rule 

of thumb, the intensity crosstalk of neighboring channels 

must be at least 20 dB below the target signal level. This 

type of crosstalk can be dealt with by using a high quality 

optical filter to eliminate all unwanted signals outside of the 

target channel bandwidth. 

Interference Filter: An optical filter consisting of multiple 

layers of evaporated coatings on a substrate, whose spectral 

properties are the result of wavelength interference rather 

than absorption. 

Ion-assisted Deposition: A technique for improving the 

structure density of thin-film coatings by bombarding the 

growing film with accelerated ions of oxygen and argon. 

The kinetic energy then dissipates in the film, causing the 

condensed molecules to rearrange at greater density. 

Optical Density (OD): Units measuring transmission 

usually in blocking regions. Conversion: -log¹⁰T = OD. For 

example, 1% transmission is .01 absolute, so -log¹⁰ (0.01) 

= OD 2.0. 

Optimized Blocking: To conserve the most energy in 

the transmission band by controlling only the out-of-band 

region of detector sensitivity. 

Peak Transmission (Tpk): The maximum percentage 

transmission within the passband. 

Polarization: At non-normal AOI, an interference filter’s 

spectral performance in p-polarized light will differ from its 

performance in s-polarized light. 

Protected Coatings: The process by which two or more 

substrates, coated with thin film depositions, are assembled 

together using an index-matching optical epoxy. 

QMAX or QuantaMAX: Surface coated single substrate 

designs with steep edges, very high transmission and no 

registration shift. 

S 

T 

Reflection (R): The return of light from a surface with no 

change in its wavelength(s). 

Signal to Noise Ratio (S/N): The system ratio of the 

integrated energy within the passband envelope to the 

energy outside this envelope and within the free spectral 

range. 

Slope: The rate of transition from attenuation (defined 

as 5% of peak transmission) to transmission (defined as 

80% of peak transmission). Slope = (lambda 0.80 - lambda 

0.05) divided by lambda 0.05. 

SP: Shortpass filters transmit wavelengths shorter than the 

cut-off and reflect a range of wavelengths longer the cutoff. 

Surface Quality: Allowable cosmetic flaws in an optical 

surface by comparison to reference standards of quality; 

usually made up of two types of standards defining long 

defects (such as scratches) and round defects (such as 

digs & pits). 

System Speed: When filtering a converging rather than 

collimated beam of light, the spectrum results from the 

integration of the rays at all of the angles within the cone. 

The peak wavelength shifts about one-half the value that it 

would shift in collimated light at the cone’s most off angle. 

Temperature Effects: The performance of an interference 

filter shifts with temperature changes due to the expansion 

and contraction of the coating materials. 

Thin Film: A thick layer of a substance deposited on an 

insulating base in a vacuum by a microelectronic process. 

Thin films are most commonly used for antireflection, 

achromatic beamsplitters, color filters, narrow passband 

filters, semitransparent mirrors, heat control filters, high 

reflectivity mirrors, polarizer’s and reflection filters. 

Transmission: The fraction of energy incident upon the 

filter at any particular wavelength that passes through the 

filter. Expressed as either percent (95%) or a fraction of 1 

(0.85). 

Transmittance (T): The guaranteed minimum value of the 

peak transmittance of the filter (not necessarily occurring at 

the centre wavelength). 




111

Frequently Asked Questions and Answers 

Q: What’s a safe Angle of 

Incidence (AOI) range for an 

interference filter? 

A: AOI is a critical parameter to consider 

when purchasing an interference filter. The 

primary effect of an increase in the AOI on 

an interference coating is a shift in spectral 

performance toward shorter wavelengths. 

That is, the principle wavelength of the 

filter decreases as the AOI increases. A 

typical interference filter will exhibit only 

minor changes in performance with a 

tilt of up to 10°. However, for certain 

narrowband filters and transition edges 

of dichroics, this slight shift may cause 

dramatic performance changes. For advice 

on how tilt affects performance please call 

one of our engineers. 

Q: Would a dichroic have better 

reflection/transmission in S or P? 

A: Simply put, reflection is better in S 

polarized light and transmission is better in 

P. This characteristic is most pronounced 

at the transition edge, where the dichroic 

is going from high reflection to high 

transmission. 

Q: Why are blocking specs so 

critical? 

A: Most people know where their signal 

of interest lies, but sometimes do not 

consider potential sources of “noise”. This 

“noise” could be autofluorescence from 

the sample, or the signal from another 

fluorophore, or even energy from their 

light source. Blocking is the feature of a 

filter that attenuates this unwanted energy 

and permits the energy from the signal 

of interest to pass through. Using filters 

designed to block unwanted signals can 

improve signal-to-noise and robustness of 

the data. 

Q: I want sharp edges, are the 3rd 

Millennium filters suitable? 

A: 3 RD Millenium filters are manufactured 

using Omega Optical's ALPHA technology , 

which produces very steep edges, capable 

of handling most application needs. 

Standard 3 RD Millenium filters utilize an 

ALPHA Gamma edge that has a 3% slope 

factor. This means that the filter’s cut-on or 

cut-off edge will go from 50% peak height 

to OD 5 by the value: 50% peak height 

wavelength x (0.03). 

3 RD Millenium filters can also be 

manufactured with an ALPHA Epsilon 

edge. This filter has a 1% edge factor and 

thus will go from 50% peak height to OD 5 

by the value: 50% peak height wavelength 

x (0.01). 

Q: Do my excitation and emission 

filters need to transmit at the 

peaks of a fluorophore’s absorption/ 

emission probability curve? 

A: Not necessarily. Although it is usually best 

to encompass as much of the probability 

peaks of a fluorophore as possible, 

sometimes other limiting factors preclude 

this solution. One example is a sample with 

multiple labels that have significant overlap 

of their emission peaks. In this case, moving 

the emission filter off the longer wavelength 

fluorophore’s emission peak can improve 

signal discrimination. 

Q: How do I clean my filters? 

A: If dust and debris are the primary 

contaminants, filters can usually be 

sufficiently cleaned by using dry air (such 

as a puff from a pipet bulb) or compressed 

air (not canned air). If the filters have oily 

substances that cannot be easily removed, 

either acetone or isopropanol can be used 

with a soft, lint free applicator, such as a 

Q-Tip or soft lens paper. 

Q: What does the arrow on the side 

of a filter indicate? 

A: Omega Optical filters should be oriented 

with the arrow pointing in the direction of 

the light path. In other words, the arrow 

points away from the light source and 

towards the detector. 

Q: Can I use an excitation filter as 

an emission filter and vice versa? 

A: Though generally not recommended, 

Omega's QuantaMAX product line is 

manufactured on single glass substrates 

with extended blocking on both excitation 

and emission filters, thus allowing for an 

excitation filter to be used as an emission 

filter, and vice versa. 

Note: QuantaMAX fluorescence filters are 

designed to function optimally as part of a 

filter set. Using a specific filter outside of 

the intended set may provide acceptable, 

though not optimal, performance. 

Q: Can I use a dichroic from my 

microscope in a flow cytometer for 

the same dye? 

A: Generally, no. Flow cytometers are 

designed to use dichroic beamsplitters 

which have different specifications than 

a fluorescence microscopy dichroic 

beamsplitter. When inquiring about a 

particular dichroic not sold as part of a filter 

set, you should always specify its desired 

application. 

Q: I’m using a filter set to image 

Cy5®, but I don’t see any image on 

the screen and I know I have enough 

dye loaded. Is the filter working 

properly? 

A: Probably, yes. Cy5 ® is a fluorophore 

which emits at the far end of the visible 

spectrum (peak at 670nm), this can make 

viewing it through the eyepiece of the 

microscope very difficult and typically a 

B/W CCD camera or PMT is needed to 

detect it. Many CCD cameras come with IR 

blocking filters housed in front of the chip 

and attenuate light from 650 nm upwards. 

This effectively blocks signal from Cy5 ® and 

similar dyes from reaching the detector. 

Consult your camera’s manual to see if the 

filter can be switched off line or removed. 

Q: How thin can my filter be? 

A: 1 mm (in limited cases 0.5 mm), and 

when reflection is not a requirement. Filter 

coatings can "bend" substrate materials, 

so the thinner the substrate, the greater 

the chance for bending, which will distort 

images. 

112 




Cleaning Optical Interference Filters 

Omega Optical interference filters are manufactured using state of the art technology for robustness and durability. 

As with all optical filters, care should be given to proper handling and cleaning. 

Directions: 

1. Avoid depositing oil from your hands onto filters by using 

finger cots. Hold filters from the edges only. For smaller 

filters use tweezers to help with handling. 

2. Blow loose dirt and particles from the surface of the filter 

using a puffer. Do not blow air from your mouth. Food and 

drink particles can be deposited. 

3. Apply isopropyl alcohol to a lint-free cotton swab and rub the 

filters surface in a circular motion, working from the center 

to edge. Gently apply pressure. Avoid rapid side-to-side 

motions. 

4. Use a puffer to evaporate excess alcohol from filter surfaces. 

5. Repeat steps 3 & 4 above using a clean, lint-free cotton 

swab with each cleaning until all surface contamination is 

removed. 

6. To complete the cleaning process wipe filter surfaces using 

lens paper gently applying pressure. 

7. Return your filter to the original plastic case or envelope 

provided. 

Note: We do not recommend the use of water, detergents or any other non-optical cleaning materials for this process. 

For an Omega Optical cleaning kit that includes the 

materials necessary to properly clean interference 

filters, please purchase from our website. 




113

online tools 

eCommerce 

Order from our website: www.omegafilters.com 

3 Choose “Shop Products”. There is a large selection of overstock products at very reasonable prices. 

3 Search by selecting one or more options from the 5 major criteria, or search by Product SKU or Description. 

3 Click “Add to Cart” and check out using our secure online store. 

Build-A-Filter 

A unique tool for finding the right filter 

3 Select your instrument or filter type. 

3 We search our database of custom, semi-custom, 

and off-the-shelf filters. Pricing comparable to catalog filters. 

3 You will receive a response in less than 24 hours. 

3 Order online. We ship your filters in 5 business days or less 

(Dependant on specifications. Expedited shipment available upon request) 

Curv-o-matic 

for stock and standard filters 

3 Select a fluorophore or filter using Curv-o-matic, 

our interactive spectral database. 

3 Choose a filter or filter set. 

3 Order online. 

114 




general information 


Unless indicated otherwise, our products are manufactured to our standard in-house specifications and tolerances. We reserve the right to 

modify or change without notice. 

Customer supplied materials 

We will handle all of customer supplied materials with the greatest care. Omega Optical accepts no liability for loss or damage to any materials 

furnished for processing. 

Quotations 

For a competitive quote, please contact us at 1.802.254.2690 (press 2 for sales) OR sales@omegafilters.com 

Quotations are valid for a period of 90 days. 

Pricing 

We value our relationship with you, our customer. We will strive to produce the best product at the most competitive price and meet your 

critical need for performance, quality, and service. Please contact us to discuss. 

Ordering 

Order from our website: www.omegafilters.com 

Order by phone: 1.866.488.1064 (toll free within USA only) • +1.802.254.2690 (outside USA) 

Order by e-mail: sales@omegafilters.com 

Order from our agents: Our extensive line of filters can be purchased directly from Omega Optical or from our worldwide 

network of agents. Please visit our website for a complete listing 

. 

Payment terms 

Terms are N30 and N45 with pre-established accounts. VISA, MASTERCARD, AMERICAN EXPRESS and PayPal are accepted. 

Shipments 

All shipments are FOB Brattleboro Vermont USA. Shipping and handling charges will be invoiced or charged to your specified carrier account. 

Warranty 

All of the products listed in this catalog are backed by a warranty of satisfaction. It is important that our customers are pleased with every 

optical filter we ship. If at any time you are not 100%satisfied, please contact us. 

Warranty does not cover obvious misuse of the product and is limited to repair or replacement of the product purchased. Omega Optical 

accepts no liability for consequential or incidental damage caused by use of the product. 




115

Delta Campus 

21 Omega Drive 

Brattleboro, VT 05301, USA 

Tel +1802.254.2690 

toll free USA 866.488.1064 

Fax +1802.254.3937 

sales@omegafilters.com 

www.omegafilters.com

optical interference filters - SPOT Imaging Solutions

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