Anti-speckle system for coherent illumination system

Abstract

This invention in phase homogenization of coherent light from illuminators used for surveillance imaging systems provides a coherent light emitter aligned with a light source ray path along an optical axis with at least two separated microdiffractive diffusers, the microdiffractive diffusers comprising holographically generated surfaces of microdiffractive structure that statistically tend to diffract light at selectable angles or distribution patterns, the microdiffractive diffusers disposed upon a substrate and separated from each other by a distance determined by wavelength phase and irradiance characteristics of the coherent light emitter and by refractive characteristics of at least two microdiffractive diffusers, followed by a homogenized exit ray path in order to produce a diffused pattern of illumination optimized for long distance surveillance imaging.

Dependencies are inferred from the claim text.