基于激光等离子体的太赫兹脉冲驱动电子偏转

Electron deflection driven by terahertz pulses from laser-plasma interactions

传统电子加速装置以射频场作为驱动场.相比之下,太赫兹辐射波长更短,加速梯度更高,是未来紧凑型电子加速装置的一种潜在驱动场.此外,太赫兹脉冲可以提供一个超快调制场用于压缩和测量电子脉宽.近年来,太赫兹场与电子的相互作用引起了广泛关注.强激光与等离子体相互作用可同时产生大能量的太赫兹脉冲和大电量的超短电子束,这一优势使其有望成为太赫兹场调控电子、太赫兹泵浦-电子探测的新型独特平台.本文以一种可行的实验布局为例,研究了激光等离子体产生的太赫兹脉冲对同向传播电子束的偏转作用.通过计算模拟,系统讨论了各参数对太赫兹场引起的电子偏转的影响,发现太赫兹电场强度或脉宽增加会使偏转现象更为显著,另外,偏转现象与太赫兹波形有关.初步的演示性实验定性验证了数值分析结果.

Traditional electron accelerators usually use the radio-frequency field as the driving field.In contrast,the terahertz radiation,with a shorter wavelength and a higher accelerating gradient,has the capability to work as the driver of compact electron accelerators in the future.In addition,the terahertz pulse can also provide an ultrafast modulated field to compress and measure the electron pulse width.Recently,the interactions between terahertz filed and electrons have attracted increasing attention.Intense laser-solid interactions can produce both a high-energy terahertz pulse and a highcharge electron beam simultaneously.This advantage enables a unique platform for the terahertz control of electrons and the terahertz pump-electron probe experiments.Here,by taking a feasible experimental layout as an example,we first investigate the interactions of a terahertz pulse with a co-propagating electron beam.Systematic discussions on the influences of several parameters on the terahertz field-induced electron deflection are presented via numerical simulations.We find that a strong terahertz electric field or the long pulse duration will enhance the deflection.Furthermore,the deflection depends strongly on the terahertz waveform.A preliminary experiment is performed to qualitatively demonstrate the relevant analysis.