高斯和平顶分布纳秒激光诱导KTP晶体损伤

Laser-induced damage of KTP crystal using nanosecond lasers with flat-top and Gaussian spatial distributions

摘要:

KTP晶体的抗激光损伤能力影响了其在高端固体激光系统中的应用。本研究利用波长1.064μm、重频10Hz、脉宽10ns和两种空间分布的光束(即高斯光束和平顶光束)的激光对KTP晶体进行了激光诱导损伤的仿真和实验。结果表明,在平顶激光和高斯激光的损伤测试中,KTP晶体的激光诱导损伤阈值分别为1.78GW/cm²和2.28GW/cm²。平顶激光辐照KTP晶体,损伤形貌为明显的烧蚀形态和裂纹,而高斯激光辐照KTP晶体时,前表面出现了典型的纳秒激光损伤形态：熔融形成的凹坑。此外,在平顶激光测试下,观察到损伤区域边缘颜色变化。

Abstract:

The laser damage resistance of KTP crystal affects its application in the high-end solid-state laser systems. This study performs the simulated and actual experiments of laser-induced damage of KTP crystal using the laser with wavelength of 1.064μm, repetition rate of 10Hz, pulse duration of 10ns and two spatial distribution beams (i.e., Gaussian beam and flat-top beam). Results indicate that the power density reaches 1.78GW/cm2 and 2.28GW/cm2 respectively when crystal damaged at a single shot test of flat-top beam and Gaussian beam. The actual laser-induced damage experiments show that the flat-top laser beam causes the obvious ablation morphology in the bulk of KTP crystal while the Gaussian beam causes the typical nanosecond laser damage morphology: the pits caused by melting and the small white spots visible to the naked eye. In addition, the color in the edge of the damage region changes in case of flat-top beam.