激光诱导典型光学窗口的表面等离子体发射光谱及动力学特性研究

Research on surface plasma emission spectra and dynamic characteristics of typical optical windows induced by laser

摘要:

光学窗口的激光诱导等离子体发射光谱及动力学特性研究对于激光损伤机理的揭示具有重要意义。基于快速成像技术和激光诱导击穿光谱技术，实验研究了1 064 nm基频和355 nm倍频激光诱导K9、熔石英、CaF₂和MgF₂等典型光学窗口的损伤过程，探讨了典型光学窗口激光诱导等离子体的时空分布规律和光谱演化行为，对比分析了激光能量密度和延迟时间对等离子体的前沿扩散高度、尺寸、温度和电子数密度等特性参数的影响；研究了光学窗口的表面等离子体发射光谱特征和成像特性及动力学演化规律，并利用微分干涉相衬显微镜分析了K9、熔石英、CaF₂和MgF₂等典型光学窗口的激光损伤形貌。损伤特征分析表明，光学窗口的表面损伤形貌与激光诱导等离子体演化特性之间存在着很强的相关性。

Abstract:

The study of laser-induced plasma emission spectra and dynamic characteristics of optical windows is crucial for revealing the mechanism of laser damage. Based on rapid imaging technology and laser-induced breakdown spectroscopy technology, experiments were conducted to investigate the damage processes of typical optical windows such as K9, fused quartz, CaF₂ and MgF₂ induced by 1 064 nm fundamental and 355 nm frequency doubled lasers. The spatiotemporal distribution and spectral evolution behavior of laser-induced plasma in typical optical windows were explored. The effects of laser energy density and delay time on the characteristic parameters such as the frontal diffusion height, size, temperature, and electron number density of the plasma were analyzed and compared. The surface plasma emission spectral characteristics, imaging properties, and dynamic evolution laws of optical windows were studied. Additionally, the laser damage morphologies of typical optical windows such as K9, fused quartz, CaF₂, and MgF₂ were analyzed using differential interference contrast microscopy. The analysis of damage characteristics revealed a strong correlation between the surface damage morphology of optical windows and the evolution characteristics of laser-induced plasma.