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.

Tunable

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.

Please note that the specifications in the “Colored Glass Alternative Filters” catalog (both hard copy and downloadable .pdf) have been modified. Current specifications are as stated on this web page.


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


Ordering Information

Model
0.5 in. dia.
Model
1 in. dia.
Model
2 in. sq.
Cut-on / Cut-off Wavelength (nm)λ @ 90% Transmissionλ @ OD 5Effective Index of Refraction ne
5CGA-22510CGA-22520CGA-225225 ±5≤ 240 nmN/A1.76
5CGA-28010CGA-28020CGA-280280 ±5≤ 295 nm≥ 250 nm2.09
5CGA-29510CGA-29520CGA-295295 ±5≤ 320 nm≥ 270 nm3.03
5CGA-30510CGA-30520CGA-305305 ±5≤ 320 nm≥ 285 nm2.35
5CGA-32010CGA-32020CGA-320320 ±5≤ 335 nm≥ 300 nm2.22
5CGA-33510CGA-33520CGA-335335 ±5≤ 350 nm≥ 317 nm2.18
5CGA-34510CGA-34520CGA-345345 ±5≤ 360 nm≥ 326 nm1.98
5CGA-36010CGA-36020CGA-360360 ±5≤ 375 nm≥ 338 nm2.26
5CGA-37510CGA-37520CGA-375375 ±5≤ 390 nm≥ 345 nm1.77
5CGA-38510CGA-38520CGA-385385 ±5≤ 400 nm≥ 360 nm1.75
5CGA-39510CGA-39520CGA-395395 ±5≤ 415 nm≥ 370 nm1.29
5CGA-40010CGA-40020CGA-400400 ±5≤ 420 nm≥ 375 nm1.83
5CGA-42010CGA-42020CGA-420420 ±5≤ 440 nm≥ 390 nm1.86
5CGA-43510CGA-43520CGA-435435 ±5≤ 455 nm≥ 400 nm1.90
5CGA-45510CGA-45520CGA-455455 ±5≤ 475 nm≥ 420 nm1.95
5CGA-47510CGA-47520CGA-475475 ±5≤ 495 nm≥ 440 nm1.41
5CGA-49510CGA-49520CGA-495495 ±5≤ 515 nm≥ 455 nm1.76
5CGA-51510CGA-51520CGA-515515 ±5≤ 535 nm≥ 485 nm1.81
5CGA-53010CGA-53020CGA-530530 ±5≤ 550 nm≥ 495 nm1.84
5CGA-55010CGA-55020CGA-550550 ±5≤ 570 nm≥ 515 nm1.77
5CGA-57010CGA-57020CGA-570570 ±5≤ 590 nm≥ 535 nm1.76
5CGA-59010CGA-59020CGA-590590 ±5≤ 610 nm≥ 555 nm1.75
5CGA-61010CGA-61020CGA-610610 ±6≤ 630 nm≥ 575 nm1.79
5CGA-63010CGA-63020CGA-630630 ±6≤ 650 nm≥ 595 nm1.74
5CGA-64510CGA-64520CGA-645645 ±6≤ 665 nm≥ 615 nm1.78
5CGA-66510CGA-66520CGA-665665 ±6≤ 685 nm≥ 630 nm1.81
5CGA-69510CGA-69520CGA-695695 ±6≤ 715 nm≥ 645 nm1.74
5CGA-71510CGA-71520CGA-715715 ±7≤ 735 nm≥ 665 nm1.70
5CGA-76010CGA-76020CGA-760760 ±7≤ 780 nm≥ 705 nm1.72
5CGA-78010CGA-78020CGA-780780 ±7≤ 800 nm≥ 710 nm1.74
5CGA-80010CGA-80020CGA-800800 ±8≤ 820 nm≥ 730 nm1.73
5CGA-83010CGA-83020CGA-830830 ±8≤ 850 nm≥ 755 nm1.79
5CGA-85010CGA-85020CGA-850850 ±8≤ 870 nm≥ 775 nm1.80
5CGA-100010CGA-100020CGA-10001000 ±9≤ 1035 nm≥ 860 nm1.76

Common Specifications - Standard Products

RoHS StatusFully compliant (without exemption granted to non-compliant colored-glass filters)
Standard Sizes0.500" dia. ± 0.005"; 1.000" dia. ± 0.005"; 2.000" 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
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 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)