Growth and characterization of nonlinear optical crystal Lu0.66La0.95Sc2.39(BO3)4

The new nonlinear optical (NLO) crystal LuxLayScz(BO3)4 (x+y+z=4) of trigonal phase has been synthesized by doping with Lu in monoclinic LaSc3(BO3)4. 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 Lu0.66La0.95Sc2.39(BO3)4 has been found to crystallize in space group R32 with cell dimensions a=9.87420(10) and c=8.0696 (7) Å. Large single crystals have been grown by a high-temperature top-seeding solution method. The UV absorption edge for polished pieces was found to be at a wavelength shorter than 200 nm. Sellmeier equations were established on the basis of the refractive indices measured by the method of auto-collimation. From modeling and optical measurements on powders, the (NLO) coefficient d11 has been determined to be 1.3 pm/V.