GROWTH AND CHARACTERIZATION OF LITHIUM TETRABORATE CRYSTALS GROWN IN PHASE-MATCHING DIRECTIONS

Li2B4O7 crystals, nonlinear crystals used in ultraviolet solid-state l asers, were grown by the Czochralski method in appropriate directions for the low-cost production of devices for fourth- and fifth-harmonic generation of a Nd:YAG laser. The crystals were 2 '' in diameter and 5 5-70 mm in length. The homogeneity of the refractive index in both cry stals was good, and the refractive index variation did not depend on t he pulling direction. However. significant scattering of the injected light beam was observed in a crystal grown in rite fifth HG direction, and the laser damage threshold of the crystal decreased. (C) 1998 Els evier Science B.V. All rights reserved.