20 January 1978 Rain Erosion-Resistant Antireflective Coatings For Infrared Windows
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Abstract
AR coatings for potential window materials (ZnS and GaAs) were developed. Emphasis was placed on developing AR coatings with rain erosion resistance. Rain erosion resistance of two-layer AR coatings (NdF3/ZnSe, LaF1/ZnSe, and ThF4/ZnSe) on small ZnS substrates was demonstrated. When exposed to a simula€ed one inch per hour rainfall at 470 mph for 20 minutes, the coatings remained intact with about 10 percent loss in transmittance. The same coatings on GaAs were severely degraded by the rain erosion test. The surface finish of the substrate appeared to be an important factor for rain erosion resistance. Coatings on substrates that satisfied the scratch-dig specification of 60-40 exhibited superior rain erosion resitance.
© (1978) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
W. W. Doerffler, W. T. Boord, H. Y. B. Mar, "Rain Erosion-Resistant Antireflective Coatings For Infrared Windows", Proc. SPIE 0121, Optics in Adverse Environments I, (20 January 1978); doi: 10.1117/12.955773; https://doi.org/10.1117/12.955773
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