Sources of intense, ultra-short electromagnetic pulses enable applications such as attosecond pulse generation, control of electron motion in solids and the observation of reaction dynamics at the electronic level. For such applications both high-intensity and carrier envelope phase~(CEP) tunability are beneficial, yet hard to obtain with current methods. In this work we present a new scheme for generation of isolated CEP-tunable intense sub-cycle pulses with central frequencies that range from the midinfrared to the ultraviolet. It utilizes an intense laser pulse which drives a wake in a plasma, co-propagating with a long-wavelength seed pulse. The moving electron density spike of the wake amplifies the seed and forms a sub-cycle pulse. Controlling the CEP of the seed pulse, or the delay between driver and seed leads to CEP-tunability, while frequency tunability can be achieved by adjusting the laser and plasma parameters. Our 2D and 3D Particle-In-Cell simulations predict laser-to-sub-cycle-pulse conversion efficiencies up to 1%, resulting in relativistically intense sub-cycle pulses.
Electron bunch generation from a plasma photocathode
在强烈的相对论性激光或粒子束的尾流中产生的等离子体波可以在厘米级的距离内将电子束团加速到千兆电子伏（GeV）的能量。这允许实现具有新兴应用的紧凑型加速器，从现代光源如自由电子激光（FEL）到能量前沿轻子对撞机。在等离子体尾场加速器中，这种每米数吉伏（GV m $^{-1}$）的尾场可以加速外部注入或从背景等离子体捕获的见证电子聚束。在这里，我们展示了光学触发的电子束团的注入和加速，产生在多组分的氢和氦等离子体采用空间对齐和同步的激光脉冲。这种“等离子体光电阴极”通过直接在等离子体腔内释放隧道电离的氦电子来实现尾流激发的注入，然后这些冷电子被迅速提升到相对论速度。注入机制可以通过光密度下降斜坡注入来访问，是高度可调的，并且为产生具有前所未有的低横向发射度、高电流和6D亮度的电子束铺平了道路。这一实验路径为基于超高亮度光束的变革性等离子体尾场加速器应用开辟了许多前景。
Rapidity-Coupled Spin Dynamics in Pulsed Laser Fields from Physics-Informed Neural Networks
Nantong University（南通大学）；Kuban State University（库班国立大学）；Joint-Stock Company “Center for Research and Development”（联合股份公司“研发研究中心”）；Shenzhen MSU-BIT University（深圳北理莫斯科大学）
Experimental demonstration of Flying-Focus enhanced Thomson scattering
Queen’s University Belfast（贝尔法斯特女王大学）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器）；University of Hamburg（汉堡大学）；Gérard Mourou Center for Ultrafast Optical Science, University of Michigan（密歇根大学杰拉德·穆鲁超快光学科学中心）；Laboratory for Laser Energetics, University of Rochester（罗切斯特大学激光能源实验室）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；ELI Beamlines Facility, The Extreme Light Infrastructure ERIC（极端光基础设施欧洲研究联盟ELI光束线设施）
Broadband hard X-ray attosecond pulses from extremely chirped electron beams
SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；Department of Applied Physics, Stanford University（斯坦福大学应用物理系）；Stanford PULSE Institute, SLAC National Accelerator Laboratory（斯坦福PULSE研究所，斯坦福直线加速器中心）
