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为了研究脉冲半导体激光器端面抽运激光晶体产生的热效应,对激光晶体瞬态温度场以及热形变场进行解析分析与计算。考虑到脉冲LD出射光具有超高斯分布,且Nd:YAG晶体热传导各向同性的特点,利用热传导Poission方程得到了超高斯分布脉冲LD端面抽运Nd:YAG晶体瞬态温度场以及热形变场的一般解析表达式,定量分析了单脉冲抽运过程中超高斯抽运光光斑半径及超高斯阶次、脉冲宽度对Nd:YAG晶体瞬态温场的影响以及准热平衡状态温度场的时变特性。结果表明,当脉冲LD端面抽运光具有3阶超高斯分布、抽运功率为80W、脉冲频率为100Hz、脉宽为200 s、钕离子掺杂质量分数为0.01的Nd:YAG晶体瞬态温度场随抽运脉冲呈现出周期性分布,准热平衡状态的温度在25.5℃到29.2℃之间成锯齿形周期分布;晶体抽运面的热形变量在0.13μm和0.19μm之间也呈现出周期性变化。该研究对于脉冲LD端面抽运全固态激光器热不敏谐振腔设计具有理论指导意义。
In order to study the thermal effect of laser diode end-pumped laser crystal, the transient temperature field and thermal deformation field of laser crystal were analyzed and calculated. Taking into account that the pulse LD has super-Gaussian distribution and the Nd: YAG crystal is isotropic, the transient temperature field and the thermal deformation field of the Nd: YAG crystal are obtained by the Poission equation. The general analytical expression is used to quantitatively analyze the influence of the spot radius of super-Gaussian pumping light and the super-Gaussian order and pulse width on the transient temperature field of Nd: YAG crystal and the time-varying characteristics of quasi-thermal equilibrium temperature field during the single-pulse pumping. The results show that the Nd: YAG crystal transient temperature of pulsed LD end-pumped with 3-order super-Gaussian distribution, pumping power of 80W, pulse frequency of 100Hz, pulse width of 200s and neodymium ion doping content of 0.01 The field exhibits a periodic distribution with the pumping pulse. The quasi-thermal equilibrium temperature is in a zigzag periodic distribution between 25.5 ℃ and 29.2 ℃. The thermal deformation of the pumping surface also shows a period between 0.13μm and 0.19μm Sexual change. The research is of theoretical significance for the design of thermally insensitive resonator for pulsed LD end-pumped solid-state lasers.