宽频带脉冲光束非线性“热像”效应理论研究  

Theoretical Analysis of Nonlinear Hot Image Effect of Broadband Pulsed Laser Beam

作　　者：王友文[1] 文双春[1] 胡勇华[1] 游开明[2] 傅喜泉[1] 

机构地区：[1]湖南大学计算机与通信学院,湖南长沙410082 [2]衡阳师范学院物理与电子信息科学系,湖南衡阳421008

出　　处：《衡阳师范学院学报》2007年第6期52-58,共7页Journal of Hengyang Normal University

基　　金：国家自然科学基金委员会与中国工程物理研究院联合基金(10576012);国家自然科学基金(60538010;10674045);国家863计划惯性约束聚变领域(2007AA804003)资助课题

摘　　要：通过理论分析和数值模拟方法,研究了高功率宽频带皮秒级(亚皮秒量级)脉冲激光非线性"热像"效应。根据宽频带光脉冲包络演化的非线性傍轴方程,在远场近似及光学薄近似条件下,得出了高功率宽频带激光非线性"热像"出现的位置及强度满足的解析关系。结果表明,"热像"形成在非线性介质后与衍射物对称的位置,"热像"强度随脉冲时间发生变化,最大强度通常发生在脉冲峰值功率时刻。通过计算机模拟,并与理论预测结果进行比较,显示两者符合较好。同时对宽频带"热像"的形成过程给出了解释,指出宽频带脉冲光束"热像"的形成类似于时间分片的连续单色光"热像"形成过程。The nonlinear hot image effect of high-power broadband pulsed laser beam has been investigated theoretically and numerically. According to the nonlinear paraxial wave equation, we derive that the functional relationship of the intensity of hot image and its location. It is shown that the image intensity varies with the＇amplitude of the pulse, and the location is situated in the equidistant down stream plane of the scatterer in an optical component located;up stream from a nonlinear element. Good a greements are shown between the theoretical prediction and the computer codes developed for pulsed beam propagation simulations based on FFT. The results indicate that the formation of hot image is equivalent to that the waveform is sliced into segments which are independently propagated through the system.

关 键 词：高功率激光 热像 宽频带脉冲光束 小尺度自聚焦 

分 类 号：O432.12[机械工程—光学工程]