Circular ND filters provide continuously variable, linear attenuation of light by rotating the filter about its center. Transmitted intensity varies as a function of the optical density range. The filter can be used for white light as well as for lasers. A large finite aperture can be attenuated by counter rotating two filters in series. Sizes are available from 25.4 mm to over 100 mm in diameter. The useable wavelength range is from 250nm to 2500nm.

Substrate Material: BK7, B270, Fused silica

Standard Linearity: +/-5% of end density value

Optical Density (O.D): 0.04-1.0;   0.4-1.5;   0.4-2.0;   0.4-3.0;   0.4-4.0

DELN can also provide Circular Stepped Variable Neutral Density (ND) Filters, These filters are available with 11 steps and are made from BK7 or UV Fused Silica substrates for visible and UV light applications.

Optical Density (O.D)