Kajita Shin, Yasuhara Ryo, Sato Masaya, Ohno Noriyasu, Tokitani Masayuki, Yoshida Naoaki
EcoTopia Science Institute, Nagoya University, Nagoya 464-8603, Japan.
Opt Express. 2013 Jul 15;21(14):17275-84. doi: 10.1364/OE.21.017275.
Multi-pulse laser induced damage threshold (LIDT) for metallic mirrors are important issue for laser diagnostics in future fusion devices. In this paper, the mechanism of multi-pulse LIDT and the influence of the slip formation and oxidization in atmosphere were investigated experimentally with a Nd:YAG pulse laser whose pulse width and wavelength are ~ 5 ns and 1064 nm, respectively. From detailed surface analysis of laser irradiated part by transmission electron microscopy (TEM), it was found that the miniaturization of crystal size and slip formation were observed on damaged area. Oxidization feature was also revealed from the TEM analysis. It was shown that the multi-pulse LIDT could be increased under vacuum condition compared with that in air atmosphere.
金属镜的多脉冲激光诱导损伤阈值（LIDT）是未来聚变装置中激光诊断的重要问题。本文利用脉宽约5 ns、波长1064 nm的Nd:YAG脉冲激光，对多脉冲LIDT的机制以及大气中滑移形成和氧化的影响进行了实验研究。通过透射电子显微镜（TEM）对激光辐照部位进行详细的表面分析，发现在损伤区域观察到晶体尺寸的减小和滑移的形成。TEM分析还揭示了氧化特征。结果表明，与空气气氛相比，在真空条件下多脉冲LIDT可以提高。
