Absorptive Neutral Density Filters
  • Three convenient sizes
  • Broadband attenuation, visible to near IR
  • Minimal surface reflections
  • 25.4 mm dia. and 50.8 mm sq. sizes are permanently marked with the optical density
  • For lower power applications
  • Custom sizes and densities available upon request

Product Description

Absorptive neutral density filters provide broadband attenuation for the visible to near-infrared region. These filters are fabricated from colored filter glass and precision polished for demanding research or OEM applications. Absorptive neutral density filters follow Lambert's absorption law which indicates that the internal transmission (i.e. transmission excluding surface reflections) of the filter is an exponential function of thickness of the filter.

Corion absorptive neutral density filters are available in three standard sizes: 12.7 or 25.4 mm diameter and 50.8 mm square. All three sizes are available individually, and the 25.4 mm dia. and the 50.8 mm square filters are also available in sets of nine filters. Each set consists of a selection of filters packaged in a protective hardwood case. All filters are shipped with a transmission curve.

Our assortment of filters permits easy creation of any desired density from 0 to 8 with 0.1 OD resolution by using individual filters or a combination of no more than two filters. When creating custom densities by stacking filters, consideration must be given to surface reflections.

Optical density (OD) is defined by the relationship:
OD = -log(T) or T = 10-OD

Due to the absorptive nature of the filter glass, use with high power lasers should be avoided. Power levels less than 30 W/cm2 are advised.

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

Optical Density
at 546.1 nm
at 546.1 nm
Quantity in Filter
Set for 25.4 mm
and 50.8 mm
Model 12.7mm
Model 25.4 mm
Model 50.8 mm
   12.7 mm Dia.25.4 mm Dia.50.8 x 50.8 mm
0.179.40%  FSR-OD10FSQ-OD10
0.1570.80%  FSR-OD15FSQ-OD15
0.350.10%  FSR-OD30FSQ-OD30
0.531.60%  FSR-OD50FSQ-OD50
0.720.00%  FSR-OD70FSQ-OD70
0.912.60%  FSR-OD90FSQ-OD90
1.53.20%  FSR-OD150FSQ-OD150
3.00.10%1 FSR-OD300FSQ-OD300
4.00.01%  FSR-OD400FSQ-OD400
Set of Absorptive
Neutral Density


MaterialNeutral density colored glass (BK 7 or equivalent for 0.04 OD)
Clear Aperture≥Central 80% of dimensions
Surface QualityE/E (60-40) per MIL-F-48616
Dimensions±0.3 mm
Thickness1.57- 4.3mm (0.04 OD, 2.9-3.1 mm)
Wedge≤3 arc min
Chamfers0.25–0.76 mm face width x 45° ±15°
Angle of Incidence
Optical Density Tolerance±4% at 546.1 nm
CleaningNon-abrasive method, acetone or isopropyl alcohol on lens tissue recommended
Laser Damage Threshold30 W/cm2 CW, typical