调QNd∶YAG环形腔外腔倍频技术研究

Study of Frequency Doubling in a KTP Crystal on Q-Switch Nd∶YAG Laser by the Resonant External Ring Cavity

用磷酸氧钛钾 (KTP)作为倍频晶体 ,对Nd∶YAG声光调Q激光的环形腔外腔倍频技术进行了实验和理论的研究 ,利用最大平均功率 5 0W、声光调Q、输出频率 10 0 5Hz、灯抽运Nd∶YAG激光器做为基频光光源 ,在基频输入功率 35W时 ,获得了大约为 31.4 %的光光转换效率的绿光输出。从实验结果分析了环形腔倍频的特性 ,指出了该方法的优缺点。从光束质量和聚焦光斑直径方面 ,对基频光和二次谐波进行了比较 ,提供了利用CCD测得光斑的部分图片 ,分析了环形腔倍频的工作原理 。

Basing on experiments and theories, we study frequency doubling in a KTP crystal on Nd∶YAG laser by the resonant external ring cavity. The Nd∶YAG laser average power is 50 W with Q-switch and its frequency is 1005 Hz. In the experiment we obtain 0.532 μm green light output with 31.4% light conversion efficiency when 1.064 μm input average power is 35 W. With the experimental results, we analyze the experimental results for the characteristics of ring cavity frequency doubling and summarize its strength and weakness. We compare fundamental frequency laser and second harmonic generation in terms of laser light quality. The thesis provides some pictures of beam focuses acquired with CCD, compares some experimental results with those pictures. We put forward a theory of the ring cavity frequency doubling in this paper.