Circular Variable Neutral Density (CVND): Attenuates Light as Filter Rotates
CVND Filters are best used in high quality optical systems to change the intensity of light from 100% to less than 0.1%. As the filter rotates the beam intensity is reduced due to the density variation of a gradient metallic coating around the filter. Available from the UV to the far Infrared, density neutrality can be achieved for narrow band applications, such as lasers, to wide band applications, such as the spectrum of white light. These filters are fully customizable in optical density gradient function, transmission gradient function, substrate type, coating materials, and size to match your application requirements.
These filters are typically specified as a linear optical density function. But, since all optical systems are not linear in operation, Reynard offers the capability of customizing the density gradient based on user defined functions. The filters can be made on a variety of substrates including N-BK7, Fused Silica, Ge and ZnSe, among several others. The typical coating material is Inconel for room temperature, low power applications. The ND coating can be enhanced to increase survivability in hostile environments using other common precious metals to match the absorption, spectral, and environmental characteristics.
