双磷酸氧钛钾晶体倍频特性的实验研究

Experiment research of frequency doubling characteristics in tandem double KTiOPO_4 crystal

为了研究双块磷酸氧钛钾(KTiOPO4,KTP)晶体串接倍频对于提高绿光倍频激光器的转换效率的作用,采用长度分别为6mm,8mm和15mm的3块KTP晶体两两串接组合进行了实验验证,绘制了单块晶体倍频和双块晶体串接倍频时的转换效率曲线,并对其进行了比较分析。结果表明,基频光功率密度从520MW/cm2到750MW/cm2时,双块KTP晶体正交串接倍频不仅比双块KTP晶体平行串接倍频的转换效率高近10%,而且比长度是两块晶体之和的单块长KTP晶体的倍频转换效率高近30%。这一实验结果对于提高绿光倍频激光器的转换效率有一定的意义。

In order to study effect of two pieces of potassium titanyl phosphate （ KTiOPQ, KTP） crystal in tandem to improve the conversion efficiency of the frequency doubling green lasers, three pieces of KTP crystal in 6mm, 8mm, 15mm long separately were used in experiments with two of them in tandem. The conversion efficiency curves of monolithic crystal and two tandem crystals were drawn. The results of scheme of two-piece KTP crystal orthogonal or parallel tandem were compared with that of a single monolithic KTP. The result shows that two-piece KTP orthogonal tandem has nearly 10% higher conversion efficiency than two-piece KTP parallel tandem, and two-piece KTP orthogonal tandem has nearly 30% higher conversion efficiency than a monolithic one in the same length with power density at fundamental frequency from 520MW/cm^2 to 750MW/ cm^2. The experimental results have a certain significance in improving the conversion efficiency of frequency doubling green lasers.