倍频激光器中KTP晶体失调研究

针对目前常用的KTP晶体，研究其倾斜失调和旋转失调对倍频激光器转换效率的影响。基于主轴坐标系变换，建立KTP晶体倾斜失调理论模型，对倾斜失调和旋转失调时激光非线性频率变换过程进行理论分析并设计实验验证。结果表明，倾斜失调时，转换效率会随着倾斜失调方向的变化出现2个大小不同的窄峰值，且倾斜角度越大，两峰值所在方向夹角越小，其余方向转换效率为零，与理论计算一致；对于旋转失调，Ⅰ和Ⅱ类相位匹配转换效率随失调角度分别呈和/2周期变化。该结果可用于倍频激光器设计。

Misalignment of KTP crystal in frequency-doubled laser

In allusion to the most commonly used KTiOPO4 (KTP) frequency-doubling crystals, the influence of tilting misalignment and rotary misalignment on conversation efficiency in frequency-doubled laser was discussed. Based on the principal axis coordinate transform, the model of tilting misalignment was established, what-s more, the process of tilting and rotary misalignment was analyzed in detail theoretically and experimentally. The results show that, in the case of tilting misalignment, two different narrow peak values of conversion efficiency appear with the variation of directions, and the bigger tilting misalignment value, the smaller included angle of peak value direction, in other direction, the conversion efficiency is zero; for rotary misalignment, type-Ⅰ and type-Ⅱphase matching conversion efficiency vary with misalignment angle for and /2 cycles, respectively.The results may provide a promising route to the design of frequency-doubled laser.