Investigation of Laser Damage Thresholds of an Output Coupler for TEA CO2 Laser

Abstract

Output couplers for TEA CO 2 lasers were made from Ge substrate coated with dielectric layers of ZnS, Ge and Y 2 O 3 using physical evaporation technique (PVD). The laser-induced damage thresholds (LIDTs) of manufactured mirrors have been investigated using an experimental setup, based on TEA CO 2 laser. The effect of preparation conditions, such as grinding, polishing and cleaning, is shown. The maximum value of LIDT about 8 J/cm 2 was achieved using a fine grinding with loose abrasive grade 3 µm, then polishing with alumina powder grade 0.3 µm and finally hot cleaning with ultrasonic waves.