发表机构
RIKEN; The University of Tokyo（理化学研究所; 东京大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究激光驱动样品处的光场驱动电子束偏转，分析不同偏振场下的偏转规律，提出可通过优化配置最小化偏转，为超短电子束时间分辨成像实验设计提供关键指导。
AI 中文摘要
自由电子束与光的耦合已实现对电子量子态的操控及超短电子脉冲的产生，但当用电子束探测激光驱动的样品时，这种耦合会引入伪影。本文从理论上研究激光激发样品位置处不可避免发生的光场驱动电子束偏转，将电子束中的电子视为经典点粒子，并聚焦于薄平面样品，系统研究了瞬时偏转幅度与光偏振、材料类型、厚度及相互作用几何的关系。对于s偏振激发场，偏转幅度严格正比于箔内的激发场幅度，使得电子束偏转不可避免；相反，对于p偏振场，由于电场、磁场的耦合以及电子-光速度失配，偏转幅度与场幅度之间呈现非平凡关系。关键的是，我们证明在高场强下，通过为给定箔材料和厚度选择最优配置，可将偏转降至最小。这些发现为设计未来使用超短电子束的时间分辨成像实验提供了关键指导。
英文摘要
While the coupling of free-electron beams and light has enabled the control of electron's quantum states and the generation of ultrashort electron pulses, it can distort the measured signal when probing a laser-driven sample with an electron beam. Here, we theoretically study optical-field-driven beam deflection that inevitably occurs at the location of a laser-excited sample. Treating electrons in a beam as classical point particles and focusing on thin planar samples, we conduct a systematic study of the instantaneous deflection amplitudes with respect to light polarization, material type, thickness, and interaction geometry. For s-polarized excitation fields, the deflection amplitude is strictly proportional to the excitation-field amplitude in a foil, making beam deflection unavoidable. Conversely, for p-polarized fields, a nontrivial relationship emerges between the deflection amplitude and the field amplitude due to the interplay of electric and magnetic fields coupled with the electron-light velocity mismatch. Crucially, we demonstrate that the deflection can be minimized even under high field strengths by selecting an optimal configuration for a given foil material and thickness. These findings provide key guidelines for designing future time-resolved imaging experiments using ultrashort electron beams.
Comments11 pages, 7 figures
