CHARACTERIZATION OF LIB3O5 CRYSTAL FOR 2ND-HARMONIC GENERATION

We present second-harmonic generation characteristics of LiB3O5 (LBO) crystal with different phase-matching lengths and comparison with those of beta-BaB2O4 crystal. A computer program of the numerical interaction method was adopted to make the theoretical calculation of second-harmonic generation conversion efficiencies of LBO with different phase-matching lengths and power densities of the fundamental beam of a Nd:YAG laser, and the calculated result was compared with the experimental one. It is seen from the calculated and experimental results that for certain power densities of the fundamental laser beam, so long as the length of the LBO crystal is selected appropriately, a high energy conversion efficiency could be obtained. For example, an optimal external energy conversion efficiency of LBO crystal of more than 70% has been attained for several 100-MW/cm2 fundamental laser beams. Experiments also showed that the crystal could be used under high power densities without any damage to the surface and the interior.