LDA侧面泵浦Nd:YAG激光器的热效应分析

 在高斯光强近似下对泵浦LD光强分布模型进行修正，建立了LDA侧面泵浦固体激光介质内热源分布的数值模型。用有限元法计算模拟了三角均匀分布侧面泵浦结构激光棒瞬态温升过程及稳态温度分布情况。讨论比较了泵浦源的高斯强度近似和均匀强度近似下激光棒内温度分布情况，并对激光棒的类热透镜的焦距进行实验测量。实验和数值计算说明了LDA泵浦结构和冷却场的非均匀分布使实际温度场偏离均匀泵浦时的二次曲线分布模型，激光晶体热效应产生的类透镜会聚作用的不对称导致了激光器输出光束质量在x，y方向上的不同。

Analysis of thermal effect in LDA side pumping Nd:YAG solid state lasers

The pump LD intensity distribution model under the Gaussian intensity approximate condition was revised,and the numerical model of the temperature field was established in the crystal cylinder of diode side-pumping solid state laser.The temperature field and warming process of the transient and steady state in the laser rod by symmetrical trigonal side-pumping were simulated using the finite element analysis method.The temperature field distributions in the laser crystal of the Gaussian intensity and uniform intensity hypothesis were presented and compared,and the thermal lens focus of the crystal cylinder was measured experimentally.It is concluded that the LDA pumping structure and the non-uniformity of the cooling field make the experiment results divergent from those of the simulation model of uniform pumping,and the non-uniformity of the lens-like focusing makes different beam quality along the x and the y axes.