Newport’s Circular Variable Neutral Density Filter is designed to attenuate the wide spectrum of low energy laser light from UV to near IR wavelength. The optical density gradient varies from 0–1.0, 0-2.0 and 0-4.0 around a disc by simply rotating the filter from 0 to 360 degrees. Fused silica substrate for these ND filters allows the transparency from 250-2500 nm range. The linear change in optical density is achieved by fine Inconel coating that allows the controlled linear attenuation of light beam in the designated optical density range for wide spectrum of light. The second surface of this filter is coated with a broadband visible antireflection coating to minimize the reflective loss from the second surface.