连续激光二极管端泵Tm:YAG晶体棒热效应

Thermal effect of continuous laser diode end-pumped Tm∶YAG crystal rod

根据激光二极管端面泵浦激光晶体工作特点的分析,建立了激光二极管端面泵浦Tm∶YAG晶体棒热模型,利用热传导理论,用有限元分析法对晶体棒的温度场、热应力场和端面形变量进行了数值计算。分析了激光能量分布不同的激光光束(圆形高斯光斑、椭圆形高斯光斑、圆形平顶光斑、方形平顶光斑)、泵浦光斑半径、Tm ^(3+)掺杂浓度对激光棒内部温度场分布及端面形变量的影响,并绘制三维分布图。结果表明,在稳定状态下,若激光二极管泵浦功率为30 W、泵浦光斑半径为400μm时,掺杂浓度为3.5at.%的Tm∶YAG晶体棒泵浦面的最高温升为124.55℃,其泵浦面的最大应力为246 MPa,沿晶体z轴最大应力为209 MPa,泵浦面最大热形变量为0.888μm。该研究为实现Tm∶YAG激光器的设计提供了理论指导。

In this paper,based on the analysis of the operation characteristics of laser diode end-pumped laser crystal,a thermal model of laser diode end-pumped Tm∶YAG crystal rod is established.The temperature field,thermal stress field and end-pumped crystal rod are numerically calculated by finite element method using heat conduction theory.The effects of laser beam with different laser energy distribution(circular Gaussian spot,elliptical Gaussian spot,circular flat top spot,square flat top spot),pump spot radius and Tm ^(3+)doping concentration on the temperature field distribution and end surface shape variables of laser rod are analyzed,and plotted in three-dimensional distribution diagrams.The results show that under the stable state,if the laser diode pump power is 30 W,and the pump spot radius is 400μm,the maximum temperature rise of the pump surface of the Tm∶YAG crystal rod with the doping concentration of 3.5at.%is 124.55℃,and the maximum stress of the pump surface is 209 MPa along the crystal z axis.The maximum heat shape variable of the pump surface is 0.888μm.This study provides theoretical guidance for the design of Tm∶YAG laser.