腔外旋转泵浦的Nd∶YAG固体激光器研究

固体激光器的热管理仍然是高功率激光系统发展的一个持续挑战。在激光系统中增益介质和泵浦光之间引入相对运动是一种高效的热管理方案。针对静止泵浦，旋转增益介质泵浦以及泵浦光旋转泵浦3种泵浦方式，借助有限元数值模拟方法分析了Nd∶YAG晶体的温度分布。泵浦光以800 r/min旋转时，在35 W泵浦功率下，使用标准的热沉冷却技术，晶体的最高温度达到约36 ℃，仅增加约16 ℃，这远低于静止泵浦时的142 ℃。实验设计并演示了一种腔外旋转泵浦的Nd∶YAG激光器，得到了12.2 W的1064 nm连续输出，斜率效率为37.2%，这大于静止时的35.1%，实验结果与理论结果相符合。研究表明，腔外旋转泵浦的固体激光器拥有高效的热管理。

Research on Nd∶YAG solid-state laser with extracavity rotatory pumping

Thermal management in solid-state lasers is still a challenge in the development of high-energy laser systems. Introducing relative motion between the pump beam and the gain medium in the laser system is an efficient thermal management scheme. The temperature distribution of Nd∶YAG crystal was analyzed by means of finite element numerical simulation for static pumping, rotating gain medium pumping and pump-beam rotating pumping. Rotated at 800 r/min with standard heat-sinking cooling the disk temperature increased by only 16 ℃ reaching a maximum temperature of ～36 ℃, which is much lower than ～142 ℃ at static pumping. Experimentally, we designed and demonstrated a Nd∶YAG laser with the extracavity rotatory pumping, and obtained a 12.2 W output of 1064 nm with a slope efficiency of 37.2%, which is greater than the 35.1% at static pumping. The experimental results were coinciding with the theoretical simulation. The study shows that the solid state laser with extracavity rotatory pumping displays greatly enhanced thermal control.