ANTIREFLECTION COATINGS ON KC1 SINGLE-CRYSTAL WINDOWS WITH LOW OPTICAL LOSS

A suitable design of a three-layer antireflection coating based on ZnS e and PbF2 layers on KCl windows for CO2 laser radiation is chosen to match the requirements for a low loss and moisture-protection coating. It is deposited on KCl plates by conventional and low-energy ion-assi sted thermal evaporation. The local absorptance at different places bo th at the interfaces and in the volume of the layers is measured by th e photothermal deflection technique at 10.6 mu m. A considerable decre ase of the local absorptance is observed in the coating deposited by t hermal evaporation with Ar-ion bombardment of energy 40 eV. Conclusion s regarding the absorptance value distribution in the depth of the coa ting are drawn.