Growth and characterization of a new nonlinear optical crystal Ca5(BO3)3F

A new nonlinear optical crystal calcium fluoroborate (Ca5(BO3)3F) has been grown successfully using LiF as a flux for the first time. Phase diagram of the pseudobinary Ca5(BO3)3F–LiF system within the composition range from 10 to 60 wt% LiF was investigated by X-ray powder diffraction and differential thermal analysis. Our experiments demonstrated that the composition of LiF from 15 to 35 wt% was beneficial to the growth of Ca5(BO3)3F crystals in Ca5(BO3)3F–LiF system. Transmission spectrum was recorded from 185 to 3000 nm, which showed that the UV cutoff for Ca5(BO3)3F crystal was about 190 nm. Second-harmonic generation efficiency was measured from Kurtz's powder technique, which indicated that Ca5(BO3)3F could be phase matchable, and second-harmonic generation efficiency of Ca5(BO3)3F was about two times as large as that of KDP. Ca5(BO3)3F has potential application as a nonlinear optical material in UV region.