基于等离子体镜的太赫兹单脉冲选择方法

研究了一种用于中国工程物理研究院太赫兹自由电子激光装置(CTFEL)输出的太赫兹的单脉冲选择方法，以满足一些对太赫兹脉冲的时间分辨率和峰值强度提出较高要求同时要保证较低平均功率的实验的需要。利用自诱导等离子体开关技术，太赫兹能够被短脉冲激光打靶产生的等离子体镜反射，从而使等离子体镜可以作为门控开关，选出单个太赫兹微脉冲。通过理论分析计算出等离子体临界密度和激光功率密度阈值，采用辐射流体模拟软件对激光打靶过程进行数值模拟。模拟结果表明，激光激发出的等离子体密度远大于临界密度。由此证明了实验的可行性，进而给出实验所需装置的参数指标以及实验光路设计。

Theoretical analysis and experimental design of terahertz single-pulse picking based on plasma mirror

China Academy of Engineering Physics Terahertz Free Electron Laser(CTFEL) needs a terahertz switch for picking of single-pulse, which can facilitate the experiments that require high peak power but low average power. With the self-induced plasma switching technology, single pulses can be reflected by a plasma mirror on a slab that is generated by short pulse laser. The critical density of the plasma and the threshold of the laser power density are calculated and the numerical simulation of the laser targeting process is carried out by using the radiation fluid simulation software. The simulation results show that the plasma density generated by the laser is much larger than the critical density, which proves the feasibility of the experiment. In addition, the parameters of the experimental equipment and the experimental optical path design are given.