宽带太赫兹脉冲单发测量技术研究

Terahertz (THz) technology develops rapidly in the past decades. Lots of research results show that broadband terahertz spectroscopy has great potential applications in biology, medicine , chemistry, agriculture and other areas. In the development and utilization of terahertz pulses, efficient and sensitive detection of terahertz signals is still challenging. The most popular method for terahertz detection is terahertz time-domain spectroscopy which is realized by scanning a probe pulse. However, in the case of recording single-shot terahertz pulse waveform or diagnosis of unrepeatable or irreversible physical process by terahertz pulses, this technique of terahertz detection doesn't work. Developing a new technique to realize single-shot terahertz measurement is an urgent demand for wider applications of terahertz technology in various fields. In this proposal, a new type of detection technique for single-shot terahertz pulse measurement based on dual-echelon and two-dimensional electro-optical imaging is developed. This technique will be used for measuring strong terahertz radiation from interaction of a 10 TW laser beam and solid / gas targets. Realization of the technique on single-shot broad bandwidth terahertz pulse measurement has great contributions to the development of novel terahertz radiations and the applications of terahertz spectroscopy.

宽带太赫兹波技术近几年飞速发展，各项研究表明宽带太赫兹光谱在生物、医学、化学、农业及其他领域均具有巨大的应用潜力。在太赫兹波的开发和利用中，太赫兹脉冲信号的高效、灵敏检测极具挑战性。普遍采用的检测方法是扫描式的太赫兹脉冲时域光谱技术。但是，如探测时需要记录下单发的太赫兹脉冲波形、或者利用太赫兹脉冲对不可重复的或不可逆的物理和化学过程进行诊断时，无法使用这种扫描式太赫兹检测方法，发展太赫兹脉冲单发测量技术是太赫兹技术在各领域应用深入开展的迫切需求。本项目拟发展一种新型的基于梯形反射镜对的二维电光成像太赫兹脉冲单发测量技术，并将其用于检测10 TW强激光与固体和气体靶作用产生的太赫兹脉冲辐射。研究形成的宽带太赫兹脉冲单发测量技术对新型太赫兹辐射源的开发、太赫兹波的光谱研究及应用有重要的科学意义和应用价值。

围绕本项目的研究计划和研究目标，主要开展了基于梯形反射镜对的电光成像太赫兹脉冲单发测量技术的研究，同时研究强激光与气体靶作用产生宽带强太赫兹脉冲辐射的物理机制，探索产生新型可控的强太赫兹辐射的新技术和新方法。在强激光与气体靶作用辐射宽带太赫兹脉冲的新产生机制理论/实验研究以及等离子体产生太赫兹辐射的波形、偏振、频谱、强度和辐射方向等的调控方面都取得了显著进展：提出了基于飞秒强激光与气体靶作用产生超宽带强太赫兹辐射的偶极阵列辐射机制，基于该理论模型，实现了对强激光激发的等离子体中辐射的宽带太赫兹脉冲载波包络相位、偏振态、辐射角分布、频谱和强度等参数的灵活操控，首次实现在小型化的激光等离子体装置上产生各项参数可控的宽带强太赫兹辐射，为开辟强太赫兹辐射应用奠定基础。