∅25.4 mm, Reflective ND Filter, Optical Density: 0.4

These Ealing reflective filters use a layer of inconel on a flat polished substrate. Inconel has the property that it is neutral over a large wavelength range. It also adheres well and can be controllably deposited to assure precise reflectance and transmittance values. These filters are supplied on fused silica substrates. The fused silica substrates will cover a wavelength range from 280 nm-2 μm. Since the attenuation mechanism is reflection these may also be used as effective beamsplitters.

Dimensions Tolerance: +0/-0.508 mm for 25.4 mm
Clear Aperture: 80% of central diameter
Spectral Range: 280-2000 nm
Optical Density Tolerance: ±10% of density at 546.1 nm