The invention provides a compound cesium fluoborate, a
nonlinear optical crystal with the cesium fluoborate, methods for preparing the compound cesium fluoborate and the
nonlinear optical crystal and application of the compound cesium fluoborate and the
nonlinear optical crystal. A
chemical formula of the compound is CsB<4>O<6>F, the molecular weight of the compound is 291.15, and the compound is of a
crystal structure and is prepared by the aid of
solid-
phase synthesis processes or vacuum packaging processes. A
chemical formula of the
nonlinear optical crystal is CsB<4>O<6>F, the molecular weight of the
nonlinear optical crystal is 291.15, the
nonlinear optical crystal belongs to orthorhombic crystal systems, space groups of the nonlinear optical crystal are Pna2<1>,
crystal cell parameters of the nonlinear optical crystal include that an a is equal to 7.9241 , a b is equal to 11.3996 , a c is equal to 6.6638 and an alpha, a beta and a gamma are equal to 90 degrees, and the unit
cell volumes of the nonlinear optical crystal are 601.95 <3>. Frequency doubling effects of the nonlinear optical crystal is approximately two times frequency doubling effects of KH<2>PO<4> [KDP (
potassium dihydrogen
phosphate)], and
ultrasonic absorption edges of the nonlinear optical crystal are shorter than 190 nm. The nonlinear optical crystal is grown from the CsB<4>O<6>F by the aid of melt processes, high-temperature solution processes, vacuum packaging processes, hydrothermal processes or room-temperature solution processes. The compound cesium fluoborate, the nonlinear optical crystal, the methods and the application have the advantages that the nonlinear optical crystal is free of deliquescence in air, is good in
chemical stability and can be applied to all-
solid-state
laser devices as an
ultraviolet nonlinear optical crystal or deep
ultraviolet nonlinear optical crystal.