摘要:
The invention is directed to preparing optical elements having a thin, smooth, dense coating or film thereon, and a method for making such coating or film. The coated element has a surface roughness of
摘要:
The invention is directed to single crystal alkaline earth metal fluoride optical elements having an adhesive, hermetic coating thereon, the coating being chemically bonded to the surface of the metal fluoride optical element with a bonding energy >4 eV and not merely bonded by van de Walls forces. The materials that can be used for coating the optical elements are selected from the group consisting of SiO 2 , F-SiO 2 , Al2O 3 , F-Al2O 3 , SiON, HfO 2 , Si 3 N 4 , TiO 2 and ZrO 2 , and mixtures (of any composition) of the forgoing, for example, SiO 2 JHfO 2 and F-SiO 2 /ZrO 2 . The preferred alkali earth metal fluoride used for the optical elements is CaF 2 . Preferred coatings are SiO 2 , F-SiO 2 , SiO 2 /ZrO 2 and F-SiO 2 /ZrO 2 .