离散效应对高强度激光三次谐波转换的影响  

Walk-off in the third harmonic generation

作　　者：赵华君[1] 冯国英[1] 朱启华[2] 张清泉[2] 陈建国[1] 

机构地区：[1]四川大学电子信息学院,四川成都610064 [2]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《强激光与粒子束》2004年第10期1277-1280,共4页High Power Laser and Particle Beams

基　　金：中国工程物理研究院 国家自然科学基金委联合基金资助课题(10176019)

摘　　要：　使用分步傅里叶变换和四阶龙格库塔法(R K),对高强度激光以Ⅰ/Ⅱ类角度失谐方式,在KDP晶体中的谐波转换进行了研究,详细讨论了离散效应对三次谐波转换的影响。结果表明,离散效应不但降低了三次谐波转换效率,而且使谐波光束质量显著降低;初始入射基频光束腰半径较小时,离散效应是二次谐波转换和三次谐波转换效率降低的主要因素,失谐角对三次谐波转换的影响较小;随着束腰半径的增加,离散效应的影响逐渐减小,失谐角对三次谐波转换的影响逐渐增加。The third harmonic conversion of type I/type II angle-detuning scheme of KDP is studied. And the effects of the walk-off in the third harmonic generation is investigated. A split-step algorithm based on the Fast Fourier Transform and a Runge-Kutta integrator is used. As a result, the walk-off decreased not only the tripling efficiency but also the harmonic beams quality. When the waist radius of the fundamental wave is small, the walk-off is the main factor that makes the SHG and THG conversion efficiency decrease, while the effect of detuning angle is little. As the waist radius of the fundamental wave increases, the effect of the walk-off slowly reduces and the effect of detuning angle increases.

关 键 词：离散效应 三次谐波转换 高斯光束 KDP晶体 

分 类 号：O437.1[机械工程—光学工程]