Growth and optical properties of a promising Deep-ultraviolet birefringent crystal Ba2Mg(BO3)2

A colorless crystal of Ba2Mg(BO3)2 about 37 × 25 × 17 mm3 has been grown successfully by the Kyropoulos method. Thermal analyses results show that Ba2Mg(BO3)2 melts congruently. The phase purity of the raw materials and the grown crystals were confirmed by powder X-ray diffraction. Ba2Mg(BO3)2 exhibits a low UV cutoff of 187 nm and high transmittance below 3000 nm. The refractive indices of the crystal have been measured and the the least-squares fitting method was used to obtain the Sellmeier dispersion equations. The results indicate that Ba2Mg(BO3)2 is a potential birefringence crystal with large birefringence of 0.10422 at 546 nm.