【摘要】 为解决百瓦级绿光激光器腔内倍频非线性晶体的热效应问题,以解析分析为基础,研究了谐振腔内多模振荡状态下非线性晶体的温度场分布。通过对激光谐振腔内非线性晶体工作特点的分析,建立了腔内多模倍频方形KTP晶体的热分析模型,给出了归一化的多模光束分布表达式。利用热传导方程,得到了多模倍频方形非线性晶体温度场的一般解析表达式。同时分析了腔内基波功率、多模光斑半径对非线性晶体温度场的影响。研究结果表明,若腔内基频光功率为500 W、束腰半径为200μm的多模光束辐射到方形KTP晶体时,晶体内的最高温升为83.14℃。研究对于减少百瓦级绿光激光器腔内倍频晶体热效应引起的相位失配,提高百瓦级绿光激光器输出功率起指导作用。更多还原

【Abstract】 In order to solve the thermal effect problem of nonlinear optical crystal with intra-cavity frequency doubling in green laser with hundred watt level,based on analytical theory,the temperature field distribution of nonlinear optical crystal was investigated in a multi-mode resonator.By analyzing the working characteristics of nonlinear crystal in resonant cavity,a thermal physical model of intra-cavity multi-mode frequency doubling KTP crystal was built,the normalized expression of multi-mode light beam was also derived.The temperature field general analytical expression of rectangular nonlinear crystal was obtained by a new solution of heat conduction equation.And some relevant parameters,such as the power and the spot radius of the intra-cavity fundamental laser beam,which would influence temperature field distribution of nonlinear crystal,were analyzed.The results show that the maximum temperature risen by rectangular KTP crystal with intra-cavity frequency doubling is 83.14 ℃ when the power of fundamental laser beam is 500 W,and the spot radius of multi-mode light beam is 200 μm.The research lays a foundation for further research,such as phase mismatching induced by the thermal effect problem of nonlinear crystal with intra-cavity frequency doubling,and plays a instructive part in improving the output power of green laser with hundred watt level.更多还原