This project will employ holographic techniques to fabricate optical materials in one step up to several hundred layers thick. The method can tailor the reflective properties in each layer. In this process, two laser beams interfere within a photosensitive layer, creating a standing wave pattern. This wave pattern controls how the coating will reflect light at a particular wavelength. By making multiple exposures at different wavelengths, one creates a structure that reflects very strongly at each recording wavelength. The technique can fabricate laser goggles and protective filters for focal plane arrays. The holographic coating techniqueallows one to make complex non-periodic structures. Unlike conventional coatings, holographic coatings can be deposited at low temperatures. Further, they can be applied to very large or highly curved optical surfaces. The coatings also protect the optics better from intense radiation that might otherwise damage or destroy the sensor. The technique permits one to integrate coatings and gratings in one structure. In addition, the technique can be applied to parts that Require unusual spectral reflectivity profiles.
