Liu Tao, Feng Chao, Xiang Dao, Liu Jiansheng, Wang Dong
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China.
Department of Physics and Astronomy, Key Laboratory for Laser Plasmas, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
J Synchrotron Radiat. 2019 Mar 1;26(Pt 2):311-319. doi: 10.1107/S1600577518018209. Epub 2019 Feb 6.
A laser plasma accelerator (LPA) has the potential to realize compact free-electron laser (FEL) radiation at the regular laboratory scale. However, large initial angular divergence and energy spread dramatically hinder ways to transport the beam and realize FEL radiation. Although methods have been proposed to solve these problems, the relatively large jitter, including transverse position jitter and energy jitter, still limits the advance of these experiments. In this paper a simple method to realize coherent harmonic generation based on a LPA beam is proposed. The scheme is very compact, adopting a high-power laser split from the driver laser, a short modulator and a short radiator which has a great tolerance to these typical types of jitter. Numerical simulations indicate that coherent third-harmonic radiation with gigawatt-level power and single spike spectra can be obtained, verifying the feasibility of the scheme and indicating the capability to generate ultrashort fully coherent radiation.
激光等离子体加速器（LPA）有潜力在常规实验室规模下实现紧凑型自由电子激光（FEL）辐射。然而，较大的初始角发散和能量展宽极大地阻碍了束流传输和实现FEL辐射的途径。尽管已经提出了解决这些问题的方法，但包括横向位置抖动和能量抖动在内的相对较大的抖动仍然限制了这些实验的进展。本文提出了一种基于LPA束流实现相干谐波产生的简单方法。该方案非常紧凑，采用从驱动激光分离出的高功率激光、一个短调制器和一个对这些典型类型抖动具有很大容忍度的短辐射器。数值模拟表明，可以获得具有吉瓦级功率和单脉冲谱的相干三次谐波辐射，验证了该方案的可行性，并表明了产生超短全相干辐射的能力。
