Infrared ND filters

Infrared Neutral Density Filters

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.

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General Specifications
Thickness:	1.0mm
Dimesnional Tolerance:	±0.2mm
Clear Aperture:	90% of outside diameter
Surface Quality:	60/40 per MIL-O-13830B
Coating Adherence:	per MIL-M-13508C
Humidity:	per MIL-STD-810F
Mechanical:	Not mounted in metal holder
Substrate Material:	Germanium
Optical Quality:	Flatness of 3 to 5 waves per inch and parallelism of 10 arc minutes or better