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-micron wavelength that use the chalcogenide glasses As2S3 and Ge45Se55 as the coating materials. Absorption in the coatings was determined by laser calorimetry at a wavelength of 10.6 microns and found to be about 0.1%. Reflectance of the coatings was also measured and found to be about 0.1%. The laser-induced damage threshold for pulsed CO2-laser radiation was also determined.