半导体激光泵浦复合晶体固体激光器的热效应

Thermal Effect of Composite Crystals Solid State Lasers Pumped by Diode Laser

为了验证复合晶体使用到半导体泵浦的固体激光器中与非复合晶体的区别,提高半导体泵浦的固体激光器的工作效率,开展了半导体激光泵浦YAP/Tm∶YAP复合晶体固体激光器的热效应的验证实验。采用有限元分析法,模拟了晶体温度及热应力的分布,并分析了热透镜长度的变化情况。结果发现,与非复合晶体相比,复合晶体的温度和热应力均有不同程度的下降,复合晶体工作时的最高温度降至其80%,热应力降至其70%。同时也验证了热透镜焦距不随非掺杂晶体长度的增大而改变,这也意味着复合晶体不能有效提高复合激光的光束质量,但是可以确保输出激光光束质量的稳定性。因此可以证实,使用复合晶体能够有效改善激光器的温度和力学特性,但不能优化固体激光器的光束质量。

In order to distinguish the characteristics of composite and traditional non-composite crys- tal used in the diode pumped solid state lasers （DPSSL）and improve the efficiency of DPSSL, the thermal effect of based on YAP/Tm： YAP composite crystal was studied. The finite element method （FEM） was employed. The temperature and heat stress were simulated, and the relationship be- tween the thermal lens and un-doped crystal length was analyzed. Experimental results indicate that the peak temperature and the thermal stress of YAP/Tm： YAP composite crystal rod decrease to less than 80% and 70% comparing with the non-composite crystal. The length of thermal lens is still constant under the condition of the variation of un-doped crystal length, which verifies that using the composite crystal in the DPSSL can benefit for the laser properties of temperature and mechanics. Nevertheless, the beam quality of DPSSL can not be optimized using the composite crystal.