Borate birefringent crystal applicable to ultraviolet (UV) or deep ultraviolet (DUV) range, and growth method and use thereof

摘要

The present invention relates to a borate birefringent crystal applicable to ultraviolet (UV) or deep ultraviolet (DUV) range, with chemical formula of Ba2Mg(B3O6)2. The borate birefringent crystal belongs to a trigonal system, with space group of R-3 wherein a=0.70528(3) nm, c=1.65520(9) nm and Z=12. The barium magnesium borate birefringent crystal is negative uniaxial (ne

主权项

1. A method for growing a borate birefringent crystal applicable to ultraviolet (UV) or deep ultraviolet (DUV) range, with chemical formula of Ba2Mg(B3O6)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.