<title>Diamond gradient index "moth-eye" antireflection surfaces for LWIR windows</title>

Abstract

An optical surface can be microscopically textured in a pattern with physical features whose dimensions are below that of the operational wavelength to produce a physical gradient in the effective optical index of refraction. The performance of such 'moth-eye' surface features, typically cones or pyramids, can be predicted based on dielectric mixture models by use of the optical properties of the base material and air. The performances of LWIR antireflective moth- eye surfaces formed in silicon, germanium and diamond are consistent with theoretical predictions.