An optical element comprises an optical element body composed of fluoride, an Al2O3 layer formed thereon, and an SiO2 layer formed on the Al2O3 layer. The Al2O3 layer is unreactive with fluorine of the fluoride. Therefore, even when the light in the deep ultraviolet region such as the light of 193 nm...http://www.google.fr/patents/US20020005990?utm_source=gb-gplus-shareBrevet US20020005990 - Optical element formed with optical thin film and exposure apparatus
Optical element formed with optical thin film and exposure apparatus
