Ultraviolet nonlinear optical crystal: CsBe_2BO_3F_2

A new ultraviolet nonlinear optical crystal CsBe2BO3F2 has been grown by the flux method with relatively greater size and thickness along the z axis. The crystal structure was determined by single-crystal x-ray diffraction analysis and the space group of it was defined as R32, belonging to the uniaxial class. Optical properties including the ultraviolet absorption edges, refractive indices, phase-matching angles, and effective nonlinear optical coefficients have been systematically determined for the first time. Based on the measured refractive indices, the Sellmeier equations were also fitted.