LD端面抽运Tm:LuAG激光器的热透镜效应研究

Research on Thermal Lensing Effect Investigation of LD End Pumped Tm:LuAG Laser

为了研究LD端面抽运Tm:LuAG晶体产生的热透镜效应,通过建立LD连续抽运下Tm:LuAG晶体吸收光场分布模型,使用Comsol软件对晶体内部温度分布进行了有限元模拟。在考虑了晶体的键合方式以及LD的抽运方式的情况下,分析了晶体吸收系数以及不同抽运功率对该晶体热效应的影响。利用ABCD光学传输矩阵理论,模拟了单棒谐振腔的稳区范围,并提出了谐振腔内采用双块Tm:LuAG晶体串接热自补偿的方式,使得温度引起的双晶体热透镜焦距互补,构建稳定工作区,给出了谐振腔稳区的参数范围,为设计高输出功率和光束质量的双LD单端抽运双晶体Tm:LuAG激光器的实验研究以及谐振腔优化提供了理论基础。

To investigate the thermal lensing effect of Tm：LuAG crystals,the temperature distribution inside the crystal was simulated by finite element method in the software‘Comsol＇to build the light-absorbing field distribution model of Tm：LuAG crystal under LD continuously pumping. Considering the bonding mode of the crystal and pumping mode of LD,the influence of different crystal absorption coefficients and pumping power on the thermal effect of crystal were analyzed. By applying the optical transfer matrix theory,the stability range of resonator with a single crystal was simulated and the method of double Tm：LuAG crystal concatenation thermal self-compensation in resonant cavity was proposed,so that the focal length of double crystal thermal lens caused by temperature was complementary and the stable workspace was constructed. The parameters of the resonant cavity stability were simulated,which provides a theoretical basis for the experimental study and resonant cavity optimization of double LD single ended pumped double crystal Tm：LuAG laser with high output power and beam quality.