Development of large KCl optics for high power CO2 laser

High quality KCl optics were developed with the maximum size of 150 mm in diameter and 30 mm in thickness and tested successfully for high power CO2 laser, the power level being up to 20 KW in this program. They are based on with joining together of newly developed techniques which are the preparation of highly pure KCl crystals, the AR coating on the polished substrates and the design of mounting holder of coated optics.