Two-layer low-absorption antireflection coating for KCl

This investigation reports the design, preparation, and performance of antireflection coatings on KCl laser windows for 10.6-microm wavelength that use the chalcogenide glasses As(2)S(3) and Ge(45)Se(55) as the coating materials. Absorption in the coatings was determined by laser calorimetry at a wavelength of 10.6 microm and found to be ~0.1%. Reflectance of the coatings was also measured and found to be ~0.1%. The laser-induced damage threshold for pulsed CO(2)-laser radiation was also determined.