Nonlinear Optical Crystal Y_xLa_ySc_z(BO₃)₄ (x + y + z = 4)

The new nonlinear optical crystal Y x La y Sc z (BO 3 ) 4 ( x + y + z = 4) has been discovered. Phase boundaries have been established in the determination of the x, y, z composition parameters that define the existence region of the trigonal huntite-type structure. From single-crystal X-ray diffraction measurements, the member Y 0.57 La 0.72 Sc 2.71 (BO 3 ) 4 has been found to crystallize in space group R 32 with cell dimensions a = 9.774(1) and c = 7.944(3) Å. Large single crystals have been grown by a high-temperature solution method. The high-energy optical absorption edge for polished pieces was found to be at a wavelength shorter than 200 nm. Sellmeier equations for the dispersion in the refractive indices were determined on the basis of curve fitting of data obtained by the method of minimum deviation. From modeling and optical measurements on powders, the nonlinear optical coefficient d 11 has been determined to be 1.4 pm/V.