多波长激光同时辐照下熔石英元件的损伤研究

Laser-induced damage in fused silica under multi-wavelength simultaneous laser irradiation

对比研究了3ω单独辐照、3ω+2ω和3ω+1ω双波长同时辐照下熔石英元件的初始损伤和损伤增长规律,重点研究3ω能量密度在其阈值附近时,低能量密度的2ω和1ω对初始损伤和损伤增长的影响,分析了波长间的能量耦合效应。结果表明:双波长同时辐照下,当2ω和1ω能量密度远低于其自身阈值时,它们对初始损伤几率和损伤增长阈值的影响可以忽略,但也会参与初始损伤和损伤增长过程,会增加初始损伤程度和损伤增长系数。基于飞秒双脉冲成像的冲击波速度测量表明,3ω和1ω同时辐照下,波长间的能量耦合效应会促进激光能量向材料沉积的效率。

The initial damage and damage growth of fused silica optical elements irradiated by 3ω alone,by two wavelengths(3ω+2ω and 3ω+1ω)at the same time were studied.When the energy density of 3ω is near its threshold,the influence of 2ω and 1ωof low energy density on the initial damage and damage growth is studied.The energy coupling mechanism between wavelengths is analyzed.The results show that:When the energy density of 2ω or 1ωis much lower than its threshold,irradiating at the same time,their effects on the initial damage probability and damage growth threshold can be ignored.But the initial damage degree and damage growth coefficient will increase.The measurement of shock wave velocity based on femtosecond dual pulse imaging shows that,when 3ωand 1ωirradiate at the same time,the energy coupling effect between wavelengths will promote the deposition efficiency of laser energy to materials.