折返点匹配的宽带二倍频实验研究  

Experimental Study of the Broadband Frequency Doubling at the Retracing Point of Phase-Matching

作　　者：韩伟[1] 郑万国[1] 曾小明[1] 朱启华[1] 

机构地区：[1]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《中国激光》2006年第1期31-33,共3页Chinese Journal of Lasers

基　　金：中国工程物理研究院科学技术基金(20050431)资助项目

摘　　要：在二次谐波转换中,基频光和倍频光的群速失配是限制转换带宽的主要因素。利用折返点匹配的宽带谐波转换技术能同时实现基频光和倍频光的相位匹配和群速匹配,理论计算表明在折返点匹配的情况下,倍频转换带宽将显著增加。分别利用厚度10 mm,氘含量12%的KD*P晶体和厚度12 mm的KDP晶体对中心波长为1053 nm,谱宽为31 nm,能量为620μJ的基频光进行折返点匹配二倍频和传统二倍频的对比实验,前者取得了22 nm的转换带宽,远大于后者7 nm的转换带宽。实验结果证实了理论计算的正确性,显示了折返点匹配宽带谐波转换技术的优越性。相应地,前者转换效率为25%,大于后者20%的转换效率,导致倍频转换效率较低的主要因素是入射基频光的光束质量和光谱质量较差。The group velocity mismatch between the fundamental pulses and second harmonic pulses is the major influence on the bandwidth of second-harmonic （SH）, however, the simultaneously phase and group-velocity matching can be achieved at the retracing point of the phase-matching curve, and the theoretical calculations show that efficient second harmonic generation with a broad bandwidth can be obtained with this method. Then the input pulses at 1053 nm with a bandwidth of 31nm and energy of 620μJ are frequency doubled with a 10 mm KD^＊ P crystal and a 12 mm KDP crystal, respectively. The output SH bandwidth in the first situation is 22 nm, much lager than 7 nm of the second configuration. The experimental results which are in agreement with the theoretical calculation show the sufficiency of the second harmonic generation configuration at the retracing point. The corresponding conversion efficiency with KD＂ P crystal is 25%, which is higher than the later one with efficiency of 20%. The major influence on the conversion efficiency is the poor beam quality of the fundamental pulses.

关 键 词：非线性光学 宽带谐波转换 折返点 群速失配 群速色散 

分 类 号：O437[机械工程—光学工程] TN248.1[理学—光学]