Yb:YAG水冷薄片激光晶体热透镜效应及补偿方法研究

热透镜是限制激光器功率提升的重要因素,薄片 结构在散热方面有一定的优势,但在 高功率泵浦下热透镜效应仍是不能回避的问题。本文从热传导方程出发,借助有限元软件, 构建了水冷薄片激光器的模型,在300 W的泵浦功率条件下对薄片晶 体的温度分布、端面变形 量和激光器整机结构的应力分布进行了详细分析,在此基础上,分析了薄片晶体安装时的机 械应力对晶体热透镜的改善作用。对比补偿前后的分析结果可知,当热沉盖板中产生100 N的 正压力对薄片晶体的热变形进行补偿时,其薄片晶体的端面变形量小于未补偿时的变形量, Yb:YAG水冷薄片激光器的热透镜效应有了明显改善。此外,适当增加薄片晶体安装时产生正 压力的大小可以更好地改善激光器的热透镜效应。

Research on thermal lens effect and compensation method ofwater cooling,thin disk Yb:YAG laser

Thermal lens is an important factor limiting the power increase of las er.The thin-disk structure has some advantages in heat dissipation,but the th e rmal lens effect under high power pump is still an unavoidable problem.Based on the heat conduction equation and finite element software,the model of water-c o oling disk laser is constructed.The temperature distribution,end-deformation a nd stress distribution of the whole laser structure are analyzed in detail under the condition of 300W pump power.On this basis,the effect of mechanical stres s on the improvement of crystal thermal lens is analyzed.Compared the analysis results after compensation,when 100N positive pressure is produced in the settl ing plate of heat sink to compensate thermal deformation of the thin-disk cryst a l,the end-deformation of thin-disk crystal is less than uncompensated one.Th e thermal lens effect of Yb:YAG water-cooling laser improved obviously.In additi o n,the thermal lens effect of laser can be improved by properly increasing the p ositive pressure when thin-disk crystal is installed.