Visible light optical filter

variableneutral-density

Variable Reflective Neutral Density Filters * Filter wheels for variable attenuation * Alloy film gives continuous variation * Optical Density from 0.04 - 2.7 * BK7 or fused silica discs These variable reflective neutral density filters provide for continuous variation of the attenuation of an optical beam. They are useful for setting the required power level in both experimental and production systems. The attenuating film is an alloy with highly neutral reflective properties over the visible spectrum. It is deposited in a continuously variable thickness over an angular range of 330 degrees of rotation of the disc. This provides a density variation from 0.04 to an optical density of 2 .7. Two types of discs are offered - BK7 and synthetic fused silica. Both have a central hole for ease of mounting. Two sizes are offered to cover most applications. See page 295 for mounted variable ND filter wheels. We offer the mounted ND filter wheels in a motorized version.