激光分布对抽运Nd:YVO4晶体热效应的影响

以解析各向异性分析理论为基础，研究矩形横截面Nd:YVO4激光晶体受到超高斯分布LD端面抽运时，激光晶体温度场分布和晶体抽运面热形变分布。通过激光晶体工作特点分析，考虑了激光分布和激光光束半径变化，建立了符合激光晶体工作状态的热模型。利用各向异性介质热传导方程的一种新求解方法，得出了矩形截面Nd:YVO4晶体的温度场、端面热形变场的通解表达式。研究结果表明：当使用输出功率为15W半导体激光器（超高斯阶次为1）端面中心入射Nd:YVO4晶体（晶体掺钕离子质量分数为0.5%）时，在抽运端面中心获得243.8?C最高温升和1.99?m最大热形变量，与实验结果一致。这种方法可以应用到其它激光晶体热问题研究中，为有效解决激光系统热问题提供了理论依据。

Influence of laser distribution on the Thermal Effect of Nd:YVO4 Crystal

Based on the analytical theory of aeolotropy, thermal distortion and temperature field distributions of laser crystal are investigated when Nd:YVO4 crystal with rectangular section is end-pumped by a laser beam of super-Gaussian distribution from a Diode Laser. By analyzing the working characteristics of the Nd:YVO4 laser crystal, a thermal model that accords with the working state of the laser crystal is established taking into account of the distribution and the radius change of laser beam. By using a kind of new solution to the heat conduction equation of the anisotropic medium, general solution expressions of the temperature field and the thermal distortion field of Nd:YVO4 crystal with rectangular section are obtained. Results show that a maximum temperature rise of 243.8?C and a maximum thermal distortion of 1.99 ?m can be obtained in the center of the pump face when the Nd:YVO4 laser crystal is pumped by a Diode Laser with a output power of 15 Watt from the center of end face (the weight percent of neodymium ion doped in the crystal equals 0.5% ), which is in agreement with experimental results. This method can also be applied to the research on the other thermal problems of laser crystal and offer theoretical basis for effectively solving the thermal problems in laser system.