Patent ID: 9360610
Filing Date: 2016-06-07
CPC Classification: C30B,G02B

Claim Text:
1. A method for growing a borate birefringent crystal applicable to ultraviolet (UV) or deep ultraviolet (DUV) range, with chemical formula of Ba 2 Mg(B 3 O 6 ) 2 , the method comprising: growing the crystal by a method of spontaneous crystallization from a melt, wherein the steps of growing crystal by the method of spontaneous crystallization from a melt are as follows: mixing and grinding a compound containing barium, a compound containing magnesium and a compound containing boron in which the molar ratio of barium, magnesium and boron is 2:1:6, then putting the mixture into a platinum crucible, heating the mixture to a molten state to obtain a mixed melt, and stirring the mixed melt for 24-48 hours; determining a saturation temperature of the mixed melt by experimenting with seed crystal, and when heating the mixed melt to 2-20° C. above the saturation temperature, putting a seed rod without seed crystal into the melt; then cooling the melt at a rate of 0.05-5° C/h for spontaneously crystallizing, then letting the crystal grow at a cooling rate of 0.05-5° C/d; and pulling the crystal out of the melt surface when the crystal grows to a size of centimeter level, and cooling the melt to room temperature at a rate of 2-100° C/h to obtain the barium magnesium borate birefringent crystal.