Fixed Neutral Density Filters (ND filters) are used to reduce the intensity of all wavelengths of light equally. The purpose of a standad photographic neutral density filters is to allow the photographer to change the aperture and exposure time to improve the image. ND filters are also used to attenuate lasers beams since the laser output cannot be adjusted without changing other properties of the laser light. Also, most lasers have a minimum operating output before being extinguished. ND filters are also used in large telescopes to cut down background noise from other objects in the sky, like the moon, and other planets and stars. Graduated ND filters are specialized ND filters that attenuate light in a radial direction. That is, the Graduated ND filter can be clear in the center and opaque at the edge. They can also be made to be opaque in the center and clear at the edge. These ND filters are the perfect filter when one wants to concentrate on a specific area of the incoming light.
Variable Neutral Density Filters are also available.
Custom optical components, thin film coatings, photolithography and optical and mechanical fabrication.