QQ客服 官方微博 反馈留言

题名	激光等离子体太赫兹辐射源偏振态的研究
作者	唐杰
学位类别	硕士
答辩日期	2015
授予单位	中国科学院上海光学精密机械研究所
导师	刘鹏
关键词	激光 空气成丝 太赫兹辐射 偏振 分子取向
其他题名	Polarization of Terahertz Radiation Generated from Laser Plasma Filament
中文摘要	随着超快强场激光技术的不断发展，空气作为非线性介质，成丝产生的太赫兹辐射具有广泛研究和应用价值。太赫兹辐射的偏振特性又决定了其电场强度和电场矢量方向的时间演化，为光和物质的相互作用的研究提供了可能条件。此外，对太赫兹偏振态的研究不仅能丰富等离子体光丝产生太赫兹辐射这一非线性过程的物理认识，还能探索并改进相干控制太赫兹偏振的新方法，因此，对太赫兹辐射偏振态的研究具有重要的物理意义和研究价值。 本文主要对周期量级光场和超快双色强激光场驱动产生的太赫兹辐射的偏振态进行研究。实验上搭建了空气成丝产生太赫兹辐射和检测的光路系统，利用等离子体光丝中的激光场变化和分子取向对太赫兹偏振进行控制，具体包含以下两个部分： 1. 研究了红外周期量级光场驱动空气成丝产生太赫兹辐射偏振态的控制方法，发现太赫兹的椭偏度和强度依赖于驱动光脉宽，而太赫兹的偏振主轴方向依赖于驱动光场的载波包络相位，结合两种实验现象可以调节驱动光场对太赫兹辐射的偏振实现全光控制。 2. 研究发现取向分子对双色光场诱导成丝产生太赫兹辐射的偏振具有调制作用。先利用取向光对空气分子取向，再通过双色场驱动等离子体光丝产生太赫兹，发现取向对太赫兹的振幅和偏振具有调制作用。改变等离子体光丝长度，发现太赫兹的偏振随着丝长调制。通过对比无取向时太赫兹辐射的偏振态，揭示取向对双色场中基频光和倍频光的相对相位的调制作用。
英文摘要	With the advances of a strong field ultrafast laser technology, terahertz radiation generated from air plasma has extensive research interests and applications. The polarization state of terahertz field determines the time evolution of the amplitude and direction of the electric field vectors, providing possible probes of the interaction of light and matter. In addition, the polarizations of THz research will not only enrich the physics understanding of this nonlinear process for plasma generating terahertz radiation, but also explore new ways of controlling the THz waveforms, thus having a very important physical significance and value of the strong laser field physics. This paper is aiming at the modulation and controlling of the terahertz polarizations generated by few-cycle pulses and two-color laser fields. In the experimental set-up with THz emission from gas plasma, we take advantage of the spatial dynamics of the THz emission in the plasma and the alignment-dependent ionization to achieve the control of terahertz polarizations: 1. A method of polarization control of terahertz waves generated by circularly polarized few-cycle laser pulses is proposed. It is found that the ellipticity and intensity of THz waves rely on the laser pulse duration, and the major axis of elliptical polarization rotates by varying the carrier envelope phase of driving laser pulses. The two phenomena can be applied to adjust the polarization state of THz emission all-optically. 2. It is found that the alignment of air molecules by the ultrafast laser pulses can modulate the polarization states and amplitude of orthogonal components of the THz emission in the two-color laser-induced plasma scheme. The variation of the length of plasma filament can also modulate the THz polarization dependent on the phase difference of the laser fields. It indicates that the filament length, the relative phase and molecular alignment can work together to manipulate the polarization of THz emission .
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16931]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	唐杰. 激光等离子体太赫兹辐射源偏振态的研究[D]. 中国科学院上海光学精密机械研究所. 2015.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。