红外与激光工程, 2016, 45 (4): 0402001, 网络出版: 2016-05-11
飞秒激光成丝过程中的太赫兹波超光速传输现象研究
Research on superluminal propagation of terahertz wave during femtosecond laser filamentation
飞秒激光 成丝 太赫兹波 超光速传输 本征模式 femtosecond laser filamentation terahertz wave superluminal propagation eigenmode
摘要
通过使用太赫兹(Terahertz, THz)时域光谱系统, 探测从不同长度飞秒激光光丝辐射出的THz脉冲, 观察到THz波在飞秒激光成丝过程中超光速传输的实验现象。进一步的分析表明: THz波在等离子体光丝区域的折射率小于其在空气中的折射率, 这是使得THz波能够在成丝过程中超光速传输的主要原因。由此可以推测: THz脉冲极有可能是在等离子体光丝中进行导引传输的。最后, 通过数值模拟获得了光丝区域内的THz本征模式, 从而验证了上述推测。
Abstract
In this paper, by investigating the terahertz(THz) waveforms emitted from different lengths of filaments via THz time-domain spectroscopy system(THz-TDS), superluminal propagation of THz wave during filamentation was observed. It implies that the refractive index of the THz wave is smaller than the unity within the filament region, and thus the THz pulse may propagate inside the filament. This hypothesis is supported by further numerical simulation, which demonstrates THz eigenmode inside the plasma filament.
刘伟伟, 赵佳宇, 张逸竹, 王志, 储蔚, 曾斌, 程亚. 飞秒激光成丝过程中的太赫兹波超光速传输现象研究[J]. 红外与激光工程, 2016, 45(4): 0402001. Liu Weiwei, Zhao Jiayu, Zhang Yizhu, Wang Zhi, Chu Wei, Zeng Bin, Cheng Ya. Research on superluminal propagation of terahertz wave during femtosecond laser filamentation[J]. Infrared and Laser Engineering, 2016, 45(4): 0402001.
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