基于交叉椭圆飞秒激光光束的多丝阵列全光调控(英文)  

Optical Switch of Multifilament Arrays by Two Noncollinear Elliptical Femtosecond Laser Beams

作　　者：曾涛 许龙 吴正茂[1,2] ZENG Tao;XU Long;WU Zhengmao(School of Physical Science and Technology,Southwest University,Chongqing 400715,China;Chongqing key Laboratory of Micro&Nano Structure Optoelectronics,Chongqing 400715,China)

机构地区：[1]西南大学物理科学与技术学院,重庆400715 [2]微纳结构光电子学重庆市重点实验室,重庆400715

出　　处：《光子学报》2022年第12期75-87,共13页Acta Photonica Sinica

基　　金：National Natural Science Foundation of China(Nos.12004316,11804283);Fundamental Research Funds for the Central Universities(No.XDJK2017C060);Experimental Technology Research Funds of Southwest University(No.SYJ2021034)。

摘　　要：提出了一种基于交叉椭圆飞秒激光双光束的多丝阵列全光调控方法,可产生规则、可重复性的多丝阵列空间分布。多丝阵列的光丝数量、空间分布可通过交叉飞秒激光光束的交叉角度、椭圆率、入射功率以及频率等进行调控。进一步,系统研究了多丝阵列产生的理论机制。对于不同频率的交叉椭圆飞秒激光双光束,交叉相位调制和初始光斑的非对称性是产生二维光丝阵列的主要机制。对于同频率的交叉椭圆飞秒激光双光束,干涉和初始光斑的非对称性导致了光丝阵列的产生。研究结果可为二维全光开关、多色泵浦探测实验等相关应用提供参考。Femtosecond laser filamentation has attracted extensive interest during the last two decades.When femtosecond laser beam power is much larger than the critical power for self-focusing,the beam breaks up into multiple filaments due to the modulation instability of the wave-front.Multiple filaments are essential for many applications,such as multichannel white-light radiation,terahertz generation,phasematched ultrafast Raman frequency conversion,and waveguiding of microwave radiation.One of the most challenging problems is to obtain high reproducibility and regular localization of the multifilament pattern.Nowadays,the multifilament array has been realized based on amplitude masks,beam ellipticity,focusing with an axicon,diffractive optical elements or a spatial light modulator.These approaches depend on control of beam wave-front amplitude,initial phase distribution or spatial waveshape by a kind of optical tuning devices.However,an all-optical switching approach to control the multifilament array has not been considered up to now,which would be particularly important for 2-D all-optical switching devices or pump-probe experiments based on multifilament arrays.Therefore,a new type of optical control of switching on and off the multifilament array pattern is explored based on two noncollinear elliptical femtosecond laser beams in this work.For the two noncollinear femtosecond laser beams with different frequencies,a simulation model of the two crossing beams propagating in air is set up,considering selffocusing,cross-phase modulation and the plasma defocusing effect based on a multiphoton ionization model.Based on this model,a numerical simulation of two noncollinear elliptical femtosecond laser beams with central wavelengths of 800 nm and 700 nm propagating in air is carried out.The radii of the two input elliptical beams along x long-and y short-axis are both set to be 0.9 mm and 0.6 mm respectively,while the input powers of both two beams are 10 Pcr.The crossing angle is 0.44°.A reproducible and regular multifi

关 键 词：飞秒激光成丝 多丝阵列 空间分布 椭圆率 交叉相位调制 

分 类 号：TN249[电子电信—物理电子学] O437.5[机械工程—光学工程]