Infrared Neutral Density Filters

From Andover

Metallic-coated neutral density (ND) filters obtain their optical density from a metal alloy coating on a substrate determined by the wavelength region of interest. Unlike the all-dielectric or absorption type, the metallic type ND filter employs a combination of absorption and reflection to reduce the intensity of light.

Provides attenuation with greater linearity over a wide spectral range
Delivers superior durability
Custom substrates available
General Specifications
Dimensional Tolerances±0.2 mm
Thickness1.0 mm
Clear Aperture90% of outside dimension
Surface Quality80/50 per MIL-0-13830B
Coating Quality80/50 per MIL-0-13830B
Coating AdherencePer MIL-M-13508C
HumidityPer MIL-STD-810F
Substrate MaterialGermanium
Optical QualityFlatness of 3-5 waves per inch and parallelism of 10 arc minutes or better
OptionalMounted in threaded ring

 Custom IR Neutral Density Filter Specifications

Size, Shape & Part Number
Transmittance (%)
Max. Deviation
From Nom. (%)
25 mm Ø50 mm Ø
0.350.12± 4.0030FNIR-25030FNIR-50
0.531.62± 2.0050FNIR-25050FNIR-50
0.625.00± 2.0060FNIR-25060FNIR-50
0.912.60± 1.5090FNIR-25090FNIR-50
1.010.00± 1.5100FNIR-25100FNIR-50
1.35.00± 1.25130FNIR-25130FNIR-50
1.53.20± 0.7150FNIR-25150FNIR-50
2.01.00± 0.25200FNIR-25200FNIR-50
3.00.10+ 0.08/-0.05300FNIR-25300FNIR-50
Set of nine filters (includes storage box)FNIR-SET-25FNIR-SET-50
Low-Power Lasers
Scientific Measurements and Research
Machine Vision and IR Imaging Applications


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