The fabricated gratings used for an 800-nm compressed laser pulse have more than 90% diffraction efficiency in the –1st order for TE polarization within 760–860 nm, and the maximum value is 94.3%. The laserinduced damage threshold (LIDT) of the gratings increases from 0.53 to 0.75 J/cm2 in the normal beam in a pulse width \tau of 40–100 fs. The LIDT of the gratings is observed a \tau^{0.25} scaling in the pulse width region. The damage morphologies of the gratings indicate that the initial damage of the gratings locates at the grating lines, a position that coincides with that of the electric field maximum.

熔石英表面激光损伤发展问题一直制约着高功率激光系统的运行通量，采用飞秒激光修复损伤点抑制损伤发展并探索修复机理。首先采用时域有限差分方法(FDTD)分析不同形状修复点的电场分布，优化修复点结构。通过改变飞秒激光脉冲能量、样品台移动参数控制修复点的形状、尺寸与深度，实现最优化修复结构。结果表明矩形修复结构降低了局部区域光强分布，经飞秒激光修复后，修复点的损伤发展阈值远高于修复前损伤点的发展阈值。采用微区电子能谱仪(EDS)分析修复点的化学成分发现飞秒修复能减少氧缺陷含量，从而降低吸收系数。因此，减少吸收性缺陷以及降低局部光强是抑制损伤发展的关键因素。

利用中心波长1064 nm、脉宽12 ns、重复频率5 Hz的NdYAG激光系统，对800 nm、0° Ta2O5/SiO2高反膜进行三种能量台阶数的激光预处理扫描改性；控制扫描速度使辐照脉冲能量重叠70%的峰值能量，辐照模式1-on-1。利用Ti：sapphire激光系统输出800 nm、135 fs超短脉冲激光进行损伤测试。结果表明，纳秒激光表面改性并未提高Ta2O5/SiO2膜飞秒激光诱导损伤阈值，三种台阶数的预处理改性均使Ta2O5/SiO2膜的阈值降低20%以上。说明缺陷(本征的或激光诱导产生的，如带间电子态)对氧化物介质膜的飞秒损伤过程有重要贡献，而这种贡献在样品经过纳秒激光改性后得以体现。

Single-pulse and multi-pulse damage behaviors of "standard" (with \lambda/4 stack structure) and "modified" (with reduced standing-wave field) HfO2/SiO2 mirror coatings are investigated using a commercial 50-fs, 800-nm Ti:sapphire laser system. Precise morphologies of damaged sites display strikingly different features when the samples are subjected to various number of incident pulses, which are explained reasonably by the standing-wave field distribution within the coatings. Meanwhile, the single-pulse laser-induced damage threshold of the "standard" mirror is improved by about 14% while suppressing the normalized electric field intensity at the outmost interface of the HfO2 and SiO2 layers by 37%. To discuss the damage mechanism, a theoretical model based on photoionization, avalanche ionization, and decays of electrons is adopted to simulate the evolution curves of the conduction-band electron density during pulse duration.