Kinetic model of optical damage in transparent crystals under continuous-wave laser irradiation

LiNbO 3 and LiTaO 3 are frequently used in second harmonic conversion of continuous-wave light from the infrared to the visible regions. Optical damage of LiNbO 3 -type crystals is a crucial issue in the high-average-power laser systems. The optical damage by a light-induced heating is investigated. We have proposed a light-induced heating by the accumulated long-lived states like polarons or self-trapped excitons. In addition to the long-lived states, point defects as color centers are created by a radiation. A new model includes these states. As a results, it is shown that a creating rate of the color center becomes a important parameter on the determination of critical power.