Optical Coatings

Abstract

This chapter presents the results of experimental studies of intermetallic compound coatings with unique properties important for high-power optics [1–3]. We have investigated the dependence of the absorption coefficients on the chemical and phase composition of vacuum condensates of copper and tin alloys in the tin concentration range from 17 to 60 %, as well as the $\gamma$ phase of copper–aluminum and copper–gallium systems in bulk and thin-film states. The minimal absorption coefficient equal to 2.1 % is obtained for a Cu₃Sn intermetallide with a tin concentration of 38–40 %. Thus we have shown that the coatings made of the electronic-type intermetallic compounds allow one to produce POE surfaces of high optical quality. The low scattering coefficient of laser radiation, high hardness and oxidation resistance, which significantly increase the lifetime of static and adaptive POEs, bond strength to the substrate, manufacturability are the main advantages of intermetallic coatings, which provided their extensive practical applications.