以解析分析理论为基础, 研究长方形Nd:YVO4激光晶体受到具有高斯分布半导体激光侧端面抽运时, 晶体温度场和热形变的分布情况。通过对激光二极管(LD)侧面抽运晶体工作特点分析, 建立了符合实际工作情况的热模型, 利用正交各向异性材料热传导方程, 得出长方形Nd:YVO4晶体温度场和热形变场通解表达式, 并提出了两种有效减小晶体热形变的方法。研究结果表明, 当使用输出功率为30 W的激光二极管侧面中心抽运Nd:YVO4激光晶体时, 在抽运端面中心获得240.0 ℃最高温升和4.73 μm最大热形变量。偏心0.6 mm时, 端面最大热形变量减少31.1%。晶体厚度减小30%时, 端面最大热形变量减少23.5%。

Based on analytical theory, the temperature field and the pumped-face thermal distortion of a rectangular Nd:YVO4 laser crystal side-pumped by a diode laser with Gaussian distribution were investigated. By analyzing the working characteristics of the laser diode (LD) side-pumped crystal, thermal physical model according with actual working conditions was built, the general expressions of temperature field and thermal distortion field of rectangular Nd:YVO4 crystal were obtained by using a new solution in heat conduction equation of orthogonal anisotropic material. Two methods of effectively reducing thermal distortion were presented. The research results showed that the maximum temperature rise of 240.0 ℃ and the maximum thermal distortion of 4.73 μm can be obtained in the center of the pump side-surface when the output power of the diode laser is 30 W. If eccentric pump center is 0.6 mm, the maximum thermal distortion is reduced by 31.3%. And if the thickness of crystal is reduced by 30%, the maximum thermal distortion is reduced by 23.5%.