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。利用波长为1.064μm、重频为10Hz、脉宽为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1.78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,即熔融形成的凹坑。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 performed the simulation and actual experiments of laser-induced damage of KTP crystal using the laser with a wavelength of 1.064μm, a heavy frequency of 10Hz, a pulse width of 10ns and two spatially distributed beams, i.e., Gaussian beam and flat-top beam. Results indicate that the laser-induced damage thresholds of KTP crystals are 1.78 and 2.28GW/cm² respectively for the flat-top beam and Gaussian beam. The laser-induced damage experiments show that the flat-top beam causes obvious ablation morphology and cracks in the KTP crystal while the Gaussian beam causes typical nanosecond laser damage on the front of surface:pits caused by melting. In addition, the color changes in the edge of the damage region can be observed in case of flat-top beam.