三维自散焦介质中的暗光束诱导亮光束聚焦  

Focusing of Bright Beam Induced by Dark Beam in Three-Dimensional Self-Defocusing Media

作　　者：阳红梅[1] 江秀娟[2] 郭旗[1] 

机构地区：[1]华南师范大学光子信息技术广东省高校重点实验室 [2]中国科学院上海光学精密机械研究所高功率激光物理国家实验室,上海201800

出　　处：《光学学报》2006年第7期1083-1090,共8页Acta Optica Sinica

基　　金：国家自然科学基金(10474023);广东省自然科学基金重点项目(04105804)资助课题

摘　　要：为了获得一种对称压缩圆光束的方法，系统研究了三维自散焦介质中亮一暗光束对的共同传输。数值结果表明：当两光束中心重合时，若抽运光（暗光束）初始振幅远大于信号光（亮光束）初始振幅，抽运光将通过交叉相位调制（XPM）诱导信号光聚焦，使得信号光的圆形光斑被对称压缩。讨论了光束参量对信号光聚焦效果的影响，发现抽运光初始振幅越大，信号光聚焦越强。当抽运光初始振幅一定时，暗光束的初始束宽存在最佳值使得信号光压缩最强。当抽运光与信号光的波长比取值为0．5～1．5时，信号光聚焦程度随着波长比的增大而有所降低。还设计了验证理论结果的实验方案。To contract the circular beam symmetrically, the co-propagation of the bright and dark beams in threedimensional self-defocusing media is studied systematically. Numrical results indicate that the signal beam is induced to the focus and symmetrically contracted during the evolution due to the cross-phase modulation effect by the pump beam, when the two beam centers are completely superposed and the initial intensity of the dark pump beam is much stronger than that of the bright signal beam. The effect of the beam parameters on the focusing performance of the signal beam is discussed, and it is found that the larger the initial intensity of the pump beam is, the stronger the focusing of the signal beam is. There exists an optimum value for the initial spot size of the dark beam for the strongest focusing of the signal beam, for a given initial pump intensity. When the wavelength ratio of the pump beam and the signal beam is 0.5-1.5, the focusing of the signal beam decreases with the rise of the ratio. And the theoretical result is validated experimentally.

关 键 词：非线性光学 诱导聚焦 数值模拟 三维自散焦介质 暗光束 交叉相位调制 

分 类 号：O437[机械工程—光学工程]