METHOD OF PRODUCING CALCIUM FLUORIDE SINGLE CRYSTAL HAVING FRACTURE RESISTANCE AND ITS USE

摘要

PROBLEM TO BE SOLVED: To provide a method of producing a calcium fluoride single crystal having high fracture resistance or breakage resistance. SOLUTION: The method of producing the calcium fluoride single crystal is utilized for producing a large size calcium fluoride single crystal having fracture resistance, and includes (a) a process for doping 1 to 250 ppm strontium in a calcium fluoride raw material, (b) a process for forming a melt of calcium fluoride by melting the calcium fluoride raw material, and (c) a process for preparing a calcium fluoride single crystal by cooling the melt of calcium fluoride formed in the process (b) so as to solidify it.