Method to produce fracture resistant calcium fluoride single crystals and applications thereof

摘要

Production of large form calcium fluoride single crystals comprises melting a calcium fluoride raw material; and cooling to solidify the melt to form a single crystal. 1-250 ppm strontium is added to the raw material to increase the breaking strength of the crystals. 10-200, preferably 80-140 ppm strontium is added to the raw material. Strontium is added as strontium fluoride (SrF2). The raw material contains 1-10 ppm sodium as impurity.