High-field high-bandwidth terahertz pulses: Generation in laser-excited gas plasmas and coherent detection in biased-air waveguides

高场高带宽太赫兹脉冲：激光激发气体等离子体的产生和偏置空气波导中的相干检测

• 批准号: 137031454
• 负责人: Dr. Mark D. Thomson, Ph.D.
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/137031454?language=en
• 关键词: field; bandwidth; terahertz; pulses; Generation

The use of femtosecond amplifier laser systems for the generation and detection of broadband terahertz (THz) pulses allows one to achieve both high THz peak fields and high bandwidth. THz spectroscopies based on these techniques are opening up new possibilities to observe non-linear THz phenomena and ultra-fast excited-state dynamics in the far- to mid-infrared. This project concerns the use of two-colour photoinduced gas plasmas for THz generation, and THz-field-induced second-harmonic generation (TFISH) in gases for coherent detection. Fundamental questions remain open concerning the physics of the plasma-THz generation, in particular the optical-THz co-propagation in the plasma medium and the resultant impact of phase-matching and saturation on the emitted THz field. We intend to address these issues using a novel combination of experimental and theoretical investigations. For the gas-TFISH detection method, we aim to extend its sensitivity by the addition of a THz waveguide structure to increase the interaction length. By optimisation of the waveguide and THz beam geometries, we anticipate at least an order of magnitude field-sensitivity improvement relative to the existing free-space implementation. A key result of this project will be the realisation of an optimised THz spectroscopy system with focal THz fields of hundreds of kV/cm and a flat frequency response extending over tens of THz.

利用飞秒放大器激光系统产生和探测宽带太赫兹（THz）脉冲，可以同时获得高的THz峰值场和高的带宽。基于这些技术的太赫兹光谱为观察远红外到中红外的非线性太赫兹现象和超快激发态动力学开辟了新的可能性。该项目涉及使用双色光致气体等离子体产生太赫兹，和太赫兹场诱导的二次谐波产生（TFISH）在气体中的相干检测。关于等离子体太赫兹产生的物理学，特别是等离子体介质中的光学太赫兹共同传播以及相位匹配和饱和对发射的太赫兹场的影响，基本问题仍然是开放的。我们打算解决这些问题，使用一种新的实验和理论研究相结合。对于气体-TFISH检测方法，我们的目标是通过增加太赫兹波导结构来增加相互作用长度来扩展其灵敏度。通过优化的波导和太赫兹光束的几何形状，我们预计至少一个数量级的场灵敏度改善相对于现有的自由空间实现。该项目的一个关键成果将是实现一个优化的太赫兹光谱系统，其焦点太赫兹场为数百kV/cm，平坦的频率响应扩展到数十太赫兹。

项目成果

Optimization of single-cycle terahertz generation in LiNbO3 for sub-50 femtosecond pump pulses.

• DOI: 10.1364/oe.21.006826
• 发表时间: 2013-03
• 期刊: Optics express
• 影响因子: 3.8
• 作者: M. Kunitski;M. Richter;M. Thomson;A. Vredenborg;Jian Wu;T. Jahnke;M. Schöffler;H. Schmidt-Böcking-H.-Schmidt-Böckin

Spatio-spectral characteristics of ultra-broadband THz emission from two-colour photoexcited gas plasmas and their impact for nonlinear spectroscopy

• DOI: 10.1088/1367-2630/15/7/075023
• 发表时间: 2013-07-25
• 期刊: NEW JOURNAL OF PHYSICS
• 影响因子: 3.3
• 作者: Blank, V.;Thomson, M. D.;Roskos, H. G.
• 通讯作者: Roskos, H. G.