双波长波片导致的脉冲分离对双色场辐射太赫兹波的影响  

Effect of Pulse Separation Induced by Dual-wavelength Wave Plate on Terahertz Waves Radiation From Two-Color Field

作　　者：王建鑫 余志强 胡俊波 苏强 郭兰军 林列[1,3] 高慧 刘伟伟[1,2] 张楠[1,2] Wang Jianxin;Yu Zhiqiang;Hu Junbo;Su Qiang;Guo Lanjun;Lin Lie;Gao Hui;Liu Weiwei;Zhang Nan(Institute of Modern Optics,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology,Tianjin 300350,China;Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Net wvork Technology,Tianjin 300350,China;School of Physical Science and Technology,Tiangong University,Tianjin 300387,China)

机构地区：[1]南开大学电子信息与光学工程学院现代光学研究所,天津300350 [2]天津市微尺度光学信息技术科学重点实验室,天津300350 [3]天津市光电传感器与传感网络重点实验室,天津300350 [4]天津工业大学物理科学与技术学院,天津300387

出　　处：《中国激光》2021年第3期173-181,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFB0504400);国家自然科学基金(11574160);中央高校基本科研业务费专项资金;天津市应用基础与先进技术研究计划(19JCYBJC16800);天津市人才发展专项计划;111计划(B16027);上海光学精密机械研究所强场激光物理国家重点实验室开放课题。

摘　　要：由于群速度的偏振依赖性,飞秒激光脉冲入射到双波长波片时出射光脉冲会分离为两个具有一定时间延迟的飞秒激光脉冲。从实验和理论模拟两方面研究了双波长波片导致的脉冲分离现象对飞秒激光双色场成丝辐射太赫兹(THz)波效率的影响。实验结果表明,脉冲分离导致的时间延迟会降低双色场辐射THz波的效率,可通过零级双波长波片缩短分离脉冲之间的时间延迟,有效提高THz波的产生效率。Objective Broadband terahertz(THz) wave has important applications in many fields,such as material identification,security inspection,optical communication,etc.It has attracted worldwide researchers’ attentions in recent years.Two-color femtosecond laser filamentation can produce THz waves with electric field as high as21 MV/cm and broad bandwidth up to 200 THz,which show significant advantages over other THz wave generation methods.In addition,THz source produced by femtosecond laser filamentation can achieve the long-distance delivery of THz wave.Due to the serious diffraction phenomenon of THz waves and the strong absorption of THz waves by water vapor in the atmosphere,THz wave cannot propagate long distance in air,while by long-distance delivery of femtosecond laser filament,THz wave can be produced in the remote locations,providing a feasible way for the related application of THz waves in the atmosphere.For the two-color femtosecond laser filamentation,the time delay,spatial walk-off,and polarization state of the fundamental and second harmonic laser beams strongly affect the generation efficiency of terahertz wave.In this paper,we demonstrate experimentally and numerically that when the polarization directions of the fundamental and the second harmonic beams are adjusted to be identical by using the dual-wavelength wave plate,obvious pulse separation will be generated due to the group delay dispersion and birefringence of the dual-wavelength wave plate.Therefore,simply adding a dual-wavelength wave plate will decrease the generation efficiency of THz wave,even a zero-order dual-wavelength wave plate is employed.By using a zero-order dual-wavelength wave plate and a dispersion compensating plate,the effect of pulse separation can be reduced,thereby increasing the terahertz generation efficiency.This work demonstrates the role of dual-wavelength wave plate and dispersion compensating plate in increasing the THz wave generation efficiency when two-color femtosecond laser filamentation is employed.Methods W

关 键 词：非线性光学 激光成丝 脉冲分离 太赫兹波 

分 类 号：O437[机械工程—光学工程]