| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method which enables production of a fluoride crystal which yields a sufficient resolving power when exposed to an F<SB>2</SB>laser. SOLUTION: The production method of the fluoride crystal comprises a crystallization step wherein an ingot is obtained through crystal growth. Before the crystallization step, a fluorinating agent comprising a metal fluoride is added to a raw material for the fluoride, and the raw material is heat-melted. Here, the concentrations of Ce, Cr, K, Fe, Mn, Na, Si and Y contained in the fluorinating agent are each adjusted to <10 ppm before use. COPYRIGHT: (C)2005,JPO&NCIPI |
