以解析分析理论为基础,研究圆截面Nd∶GdVO4激光晶体受到具有高斯分布半导体激光端面中心入射时,晶体温度场分布和抽运面热形变分布情况。通过对激光二极管(LD)端面入射晶体工作特点分析,建立了符合实际工作情况的热模型,利用热传导方程新求解方法,得出了圆形截面Nd∶GdVO4晶体温度场分布和端面热形变场通解表达式,对比分析了圆形截面和矩形截面Nd∶GdVO4晶体的热形变。研究结果表明,当使用输出功率为15 W激光二极管端面中心入射Nd∶GdVO4激光晶体时,在抽运端面中心获得187.5 ℃最高温升和1.313 μm最大热形变量。两种截面晶体具有相同的热形变形状,当截面尺寸不太大时,如果圆形截面晶体的半径等于矩形截面晶体半边长,最大热形变量将减少4.1%。这种方法还可以应用到其他圆形截面晶体热问题研究中,为有效解决激光系统热问题提供了理论依据。

Based on analytical theory, the distributions of crystal temperature field and the pumped-face thermal distortion were investigated when the Nd∶GdVO4 laser crystal with circular section was end-pumped by a semi-conductor laser with Gaussian distribution. By analyzing the working characteristics of the laser diode (LD) end-pumped crystal, thermal physical model was built, which accords with actual working conditions; the general solutions of temperature field distribution and end surface thermal distortion field of Nd∶GdVO4 crystal with circular section were obtained by using a new solution in heat conduction equation, and the thermal distortions of the crystals with circular section and rectangular section were analyzed comparatively. The research results show that the maximum temperature rise of 187.5 ℃ and the maximum thermal distortion of 1.313 μm can be obtained in the center of the pump end surface when the output power of the dioxide laser is 15 W. These two kinds of crystals with different sections have same thermal distortion shape, and when the section size of crystal is not too large, if the radius of circular section equals to half length of the side of the rectangular section, the maximum thermal distortion will be reduced by 4.1%. This method can be applied to the research on other thermal problems of crystal with circular section, which can offer theoretical basis for efficiently resolving the thermal problems in laser system.