Stoichiometric LiTaO/sub 3/ as new nonlinear material for bulk quasi-phasematching

Summary form only given. In recent years there has been increasing interest in the use of quasi-phase-matched nonlinear crystal for a variety of frequency conversion applications. Periodically poled lithium niobate (PPLN) and lithium tantalate (PPLT) have been demonstrated to give efficient second harmonic generation and optical parametric oscillation in both the cw and the Q-switched regimes. However, the performance of QPM devices using PPLN or PPLT has been limited for operation at high peak powers because of difficulty in forming gratings in samples thicker than 1 mm, and at high average power in the visible without resort to operation at high temperatures because of the onset of output beam distortion at high light intensity. These limitations are strongly related to material parameters such as a high electric field of /spl sim/21 kV/mm for ferroelectric domain reversal, and highly variable photorefractive damage resistance and optical absorption in the visible.