发表机构
National University of Defense Technology; Hunan Key Laboratory of Extreme Matter and Applications（国防科技大学; 湖南极端物质与应用重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究圆偏振激光电离原子产生的空穴环电流，利用阿秒瞬态吸收圆二色性探测其亚周期形成，并建立二色性信号与角动量投影的线性关系，为探测离子相干性提供新方法。
AI 中文摘要
原子被圆偏振少周期激光脉冲超快电离会产生空穴环电流，为磁性的超快操控提供了一条途径。本文探究了这些电流的亚周期形成过程，其环流方向由驱动场的螺旋度决定，而其大小则受残余离子的量子相干性支配。我们证明，相关的离子-光电子动力学可以通过阿秒瞬态吸收圆二色性来探测。利用维格纳-埃卡特定理，我们推导出态分辨的二色性吸收与空穴的轨道和自旋角动量投影之间的线性关系，从而将Thole-Carra磁性CD求和规则从静态X射线光谱学扩展到阿秒电子动力学。二色性信号的调制深度提供了电离注入相干性的直接光学度量，其对手性脉冲持续时间的依赖揭示了相干性建立与电离诱导退相干之间的竞争。这些发现展示了阿秒圆二色性在探测离子相干性方面的潜力，并强调了量子相干性在光与物质之间超快角动量交换中的作用。
英文摘要
Ultrafast ionization of atoms by circularly polarized few-cycle laser pulses generates a hole ring currents, offering a route for ultrafast manipulation of magnetism. Here we explore the subcycle formation of these currents whose circulation direction is determined by the driving-field helicity, whereas their magnitude is governed by the quantum coherence of the residual ion. We show that the correlated ion-photoelectron dynamics can be probed with attosecond transient-absorption circular dichroism. Using the Wigner-Eckart theorem, we derive a linear relation between state-resolved dichroic absorption and the orbital and spin angular-momentum projections of the hole, thereby extending the Thole-Carra magnetic CD sum rules from static X-ray spectroscopy to attosecond electron dynamics. The modulation depth of the dichroic signal provides a direct optical measure of the coherence injected by ionization, and its dependence on the pump-pulse duration reveals a competition between coherence build-up and ionization-induced dephasing. These findings demonstrate the potential of attosecond circular dichroism for probing ionic coherence and highlight the role of quantum coherence in ultrafast angular momentum exchange between light and matter.
Comments14 pages, 4 figures
