用变分法研究超短超强脉冲在介质中的成丝  

High Power Ultra Short Laser Pulse Filamentation Using Variational Analysis

作　　者：张颖[1] 魏晓峰[2] 朱启华[2] 应纯同[1] 郝轶聃[2] 

机构地区：[1]清华大学工程物理系,北京100084 [2]中国工程物理研究院激光聚变研究中心,绵阳621900

出　　处：《光子学报》2008年第7期1329-1333,共5页Acta Photonica Sinica

摘　　要：利用变分法将非线性薛定谔方程在形式上简化,把光束成丝等价于粒子在势阱中的运动,直观反映了自聚焦、衍射和多光子电离等机制对光束成丝的影响.实验得到了不同入射功率、光束口径、波面曲率半径等初始条件下脉冲在空气介质中的成丝过程和时间波形变化.通过半解析方法得到的结论能够定性解释成丝和多次聚焦现象等实验结果.Using variational analysis, the nonlinear equation is simplified. The filamentation dynamics is analogous to the problem of a particle moving in a potential well, then self-focusing, diffraction and multiple-photon ionization mechanisms are denoted by non dimensional symbols. The evolvement of beam power,radius,wavefront curvature,and temporal profile is discussed with different initial conditions. The results are qualitatively coincident with some major experimental observations such as filamentation and refocus phenomenon.

关 键 词：自聚焦 多光子电离 超短光脉冲 成丝 

分 类 号：O437[机械工程—光学工程]