Colored-Glass Alternative Filters
  • RoHS compliant (unconditional)
  • Steep transitions from blocking to transmission
  • Low autofluorescence
  • High transmission - >90% average (typical)
  • Excellent blocking - >5 OD
  • Patented Stabilife® coatings
  • Wavelength stability in any environment
  • Exceptional durability
  • 34 Standard cut-on wavelengths in 4 standard sizes
  • Custom cut-on wavelength availability from 225 to 1000 nm

Product Description

Newport's patent-pending Colored-Glass Alternative (CGA) filters are constructed using optical thin-film coating technology. Using Newport's patented Stabilife® coating technology, many layers of refractory metal oxide film are deposited under vacuum in a precise sequence, defining the spectral signature of the filters. Unlike Colored-Glass filters which rely upon absorption to create the filter's spectral response, CGA filters utilize optical interference phenomena to create wide bands of very-high reflectance to create the blocking region of the filters, and wide bands of very-low reflectance to create the transmission bands of the filters.

Our catalog offering of Colored-Glass Alternative filters is a series of fully-blocked, all-dielectric longwave pass filters at thirty-four (34) different cut-on wavelengths. The group of standard wavelengths was developed as a compilation of the cut-on wavelengths of longwave pass filter glasses currently offered by the major manufacturers of colored-glass filters, as well as some wavelengths that have been discontinued by these manufacturers. Four (4) different sizes are available at each wavelength: ½" diameter, 1" diameter, 2" square, and 6½" square. Standard CGA filters are typically supplied with a thickness of 1.1 mm.

In addition to our standard CGA products, we routinely provide custom products based upon the basic product concept and designs. Custom capabilities are discussed in the section following the pages devoted to our catalog products.

Steeper Slopes

Using optical interference coatings to create longwave pass filters provides some distinct advantages over using absorptive colored-glass. Transition slopes between the rejection or blocking band and the transmission band can be made much steeper using interference coatings. On average, CGA filter slopes are 3 times steeper than the transition slopes of corresponding Colored-Glass filters.

Thickness Flexibility

The spectral response of CGA filters is not dependent upon the thickness of the filters. By contrast, the degree of rejection or blocking and the cut-on wavelength of a filter constructed using colored-glass is directly dependent upon its thickness. The relationship between the thickness of absorbing colored-glass is explained by the Bouguer-Lambert Law (also known as the Lambert Law) which defines the effect on the intensity of light transmitted through an absorbing substance in respect to its thickness. This feature allows Colored-Glass Alternative filters to be manufactured using very thin substrates while maintaining the required depth of blocking, enabling their use in a variety of applications where "small & thin" are desirable features.


In addition to the abovementioned benefits of Colored-Glass Alternative filters over colored-glass filters, the cut-on wavelength of CGA filters can be tuned to slightly shorter wavelengths by positioning the filter at off-normal incidence to the source of illumination. This capability is a common phenomenon associated with thin-film optical interference coatings.

RoHS Compliant

Unlike several Yellow, Orange, and Red Colored-Glass filters, Corion Colored-Glass Alternative filters are unconditionally compliant with RoHS regulations. They do not rely on the exemption for Optical and Filter Glasses containing Lead and Cadmium that has been established by the European Parliament that is subject to periodic review for either extension or termination. As such, CGA filters are not subject to the uncertainty of the review process.

To discuss your specific requirements, please call 508-528-4411 to speak directly to one of our Technical Sales Engineers, or email us at

Ordering Information

0.5 in. dia.
1 in. dia.
2 in. sq.
6.5 in. sq.
Cut-on / Cut-off Wavelength (nm)λ @ 90% Transmissionλ @ OD 5Effective Index of Refraction ne
5CGA-22510CGA-22520CGA-22565CGA-225225≤ 260 nmN/A2.242
5CGA-28010CGA-28020CGA-28065CGA-280280≤ 365 nm≥ 250 nm1.943
5CGA-29510CGA-29520CGA-29565CGA-295295≤ 322 nm≥ 270 nm3.856
5CGA-30510CGA-30520CGA-30565CGA-305305≤ 325 nm≥ 285 nm2.725
5CGA-32010CGA-32020CGA-32065CGA-320320≤ 340 nm≥ 300 nm2.243
5CGA-33510CGA-33520CGA-33565CGA-335335≤ 345 nm≥ 317 nm2.079
5CGA-34510CGA-34520CGA-34565CGA-345345≤ 367 nm≥ 326 nm2.147
5CGA-36010CGA-36020CGA-36065CGA-360360≤ 367 nm≥ 338 nm2.085
5CGA-37510CGA-37520CGA-37565CGA-375375≤ 390 nm≥ 345 nm2.454
5CGA-38510CGA-38520CGA-38565CGA-385385≤ 405 nm≥ 360 nm2.321
5CGA-39510CGA-39520CGA-39565CGA-395395≤ 410 nm≥ 370 nm2.176
5CGA-40010CGA-40020CGA-40065CGA-400400≤ 415 nm≥ 375 nm2.174
5CGA-42010CGA-42020CGA-42065CGA-420420≤ 435 nm≥ 390 nm2.176
5CGA-43510CGA-43520CGA-43565CGA-435435≤ 450 nm≥ 400 nm1.966
5CGA-45510CGA-45520CGA-45565CGA-455455≤ 470 nm≥ 420 nm2.054
5CGA-47510CGA-47520CGA-47565CGA-475475≤ 490 nm≥ 440 nm1.948
5CGA-49510CGA-49520CGA-49565CGA-495495≤ 510 nm≥ 455 nm1.853
5CGA-51510CGA-51520CGA-51565CGA-515515≤ 530 nm≥ 485 nm1.856
5CGA-53010CGA-53020CGA-53065CGA-530530≤ 545 nm≥ 495 nm1.854
5CGA-55010CGA-55020CGA-55065CGA-550550≤ 565 nm≥ 515 nm1.861
5CGA-57010CGA-57020CGA-57065CGA-570570≤ 585 nm≥ 535 nm1.856
5CGA-59010CGA-59020CGA-59065CGA-590590≤ 605 nm≥ 555 nm1.855
5CGA-61010CGA-61020CGA-61065CGA-610610≤ 625 nm≥ 575 nm1.854
5CGA-63010CGA-63020CGA-63065CGA-630630≤ 645 nm≥ 595 nm1.856
5CGA-64510CGA-64520CGA-64565CGA-645645≤ 660 nm≥ 615 nm1.778
5CGA-66510CGA-66520CGA-66565CGA-665665≤ 680 nm≥ 630 nm1.831
5CGA-69510CGA-69520CGA-69565CGA-695695≤ 710 nm≥ 645 nm1.853
5CGA-71510CGA-71520CGA-71565CGA-715715≤ 730 nm≥ 665 nm1.777
5CGA-76010CGA-76020CGA-76065CGA-760760≤ 775 nm≥ 705 nm1.856
5CGA-78010CGA-78020CGA-78065CGA-780780≤ 795 nm≥ 710 nm1.776
5CGA-80010CGA-80020CGA-80065CGA-800800≤ 815 nm≥ 730 nm1.855
5CGA-83010CGA-83020CGA-83065CGA-830830≤ 845 nm≥ 755 nm1.775
5CGA-85010CGA-85020CGA-85065CGA-850850≤ 865 nm≥ 775 nm1.778
5CGA-100010CGA-100020CGA-100065CGA-10001000≤ 1030 nm≥ 860 nm1.776

Common Specifications - Standard Products

RoHS StatusFully compliant (without 4-year exemption granted to non-compliant colored-glass filters)
Standard Sizes0.500" dia. ± 0.005"; 1.000" dia. ± 0.005"; 2.000" sq. ± 0.010"; 6.500" sq. ± 0.010"
Active Area≥90% of filter size with film to the edge (except on 65CGA filters which may have a 0.100" maximum uncoated border on all edges)
Thickness1.1 mm ± 0.1 mm (all models except CGA-225 & CGA-280 which are 0.96 ± 0.13 mm)
Surface QualityF/F (80/50) per MIL-F-48616
Coating Abrasion Resistance, Adhesion, & HardnessMIL-C-48497
Coating Humidity ResistanceMIL-STD-810, Method 507.3, Procedure III, Modified to 40 cycles
Coating Operating Temperature Range-100 °C to 400 °C
Chemical ResistanceSR Class 1.0 per ISO 8424
Laser Damage Threshold≥ 1J/cm2 (typical) tested at 532 nm, Pulse width 10 ns, Repetition rate 20Hz
CleaningNon-abrasive method, acetone or isopropyl alcohol on lens tissue recommended
Cut-on Wavelength Tolerance± 5 nm (typical); (± 6 nm typical for NIR wavelengths)
Transmittance≥ 90% average (typical)
Range of Transmittanceλ of 90% Transmission to 2500 nm
Spectral Blocking≥OD5 to 200 nm (typical)

Custom Capability Common Specifications

RoHS StatusFully compliant (without 4-year exemption granted to non-compliant colored-glass filters)
Passband Transmittance≥90% average (typical)
Cut-on Wavelength Availability300 - 1000 nm
Spectral Blocking≥ 5 OD
Surface QualityF/F (80/50) per MIL-F-48616 (typical)
Coating HardnessMIL-C-48497
Coating Abrasion ResistanceMIL-C-48497
Coating AdhesionMIL-C-48497
Coating Humidity ResistanceMIL-STD-810, Method 507.3, Procedure III, Modified to 40 cycles
Coating Operating Temperature Range-100 °C to 400 °C
Chemical ResistanceSR Class 1.0 per ISO 8424
Filter Size Range1.0 mm sq. to 380 mm dia.
Filter Thickness1.1 mm (typical)