Radiation Hardened Dark Coating for Stray Light Suppression in Optical Systems

ZeCoat Corp will develop an x-ray hardened, black coating technology for stray light suppression. Coatings will be designed to operate over broadbands from the visible to the mid IR, and tested for x-ray tolerance and ground-storage durability. These very thin (less than 1-micron), vacuum-deposited coatings, may be applied to almost any rigid or flexible, vacuum compatible substrate such as, glass, beryllium, silicon carbide, aluminum, metal foil, or KaptonTM film. The dark coatings may be applied to a smooth mirror surface, or a slightly roughened and diffuse surface. Black coatings for stray light suppression are needed for optical sensors and seekers operating in space environments. Some space-based DoD systems must be designed for radiation tolerance to both natural radiation and man-made x-ray events. Existing blackening processes such as carbon nanotubes, black silicon, copper oxides, carbon-filled KaptonTM, and others, are often not environmentally durable, and/or are not hardened to x-ray events in space. Many state-of-the-art black coatings create particulate contamination when abraded, or when mechanically shocked. In Phase I, ZeCoat manufactured coating designs stacked in a sequence to efficiently absorb visible and near-IR light, and the designs were analyzed with an x-ray survivability analysis code. We demonstrated the feasibility of reducing the total hemispherical reflectance to less than 0.8%, the specular reflectance to less than 0.1%, and with x-ray melt fluences several times higher than our design goals. In Phase II, the coatings will be refined and the research will be extended to include X-ray exposure tests at the Double Eagle test facility. In addition, we will implement new manufacturing equipment, processes, and software, to significantly improve upon our state-of-the-art coating capabilities. These manufacturing ōupgradesö will improve the yield and lower the cost of these demanding coating designs. This research will directly benefit space-based optical systems, and missile interceptors. ZeCoat Corporation will serve as the prime contractor on the Phase II SBIR, with our focus on coating design and manufacturing technology. Fifth Gait Technology will provide support as a subcontractor, and will analyze and test the coatings for radiation survivability. Approved for Public Release | 23-MDA-11635 (9 Nov 23)