Stability of Optical Coatings in Hostile Excimer Laser Environments

摘要

E-beam evaporated SiO2 films were investigated during and after exposure to XeF laser gas components. Experimental methods and results are described, indicating that (i) impurities in the films reduce chemical film stability even without laser photons present; (ii) low energy ions from the laser plasma enhance film decomposition; (iii) mirror substrate temperature between room temperature and 100 C does not influence etching significantly.