强激光场中阿秒时间分辨的电离动力学研究

Fundamental and exploratory research on the interaction between matter and intense laser fields, such as ionization of atoms to highly charged ions, acceleration of charged particles, vacuum polarization and electron-positron pair production in extreme strong field, have become the most significant frontier of scientific research in today's physics area. Ionization of atoms in intense laser fields is the basic physical process of the interaction between intense laser field with variety of complex physical forms, showing nonperturbative and many-body correlative complex dynamics. The study on these novel ionization processes, including multi-photon ionization, tunneling ionization, over the barrier ionization, high-order above threshold ionization, nonsequential multiple ionization, auto-ionization, Fano resonance, Auger decay, interatomic Coulomb decay, and so on, has been central to understanding and harnessing strong field physics. This project aims to apply the basic quantum theory combined with semiclassical trajectory simulation to study the attosecond ultrafast process in many-electron correlated strong field ionization dynamics. We will also try to explain the latest experiments.This kind of study will enrich our understanding about the microscopic dynamical behavior of matter in extreme laser filed, and migh also help to explore possible way to probe internal electronic motion and structural changes of atoms or molecules on the attosecond time scale.

强激光与物质相互作用涉及原子的高剥离过程、带电粒子加速乃至超强场中的真空极化及正负电子对产生，是当今物理学的重要前沿研究领域，具有很强的基础性与探索性。强激光场中原子的电离过程是研究强激光与各种复杂物质形态相互作用的基础，展现出非微扰、多体关联主导的复杂动力学行为。这些电离过程包括多光子电离、隧穿电离、越垒电离、高阶阈上电离、非序列多重电离、自发电离、Fano共振、Auger衰变、以及原子间的库仑衰变等新奇现象，是强场物理研究的核心问题之一。本项目旨在应用量子理论、半经典轨道模拟方法结合最新实验进展，深入研究强场电离中多电子关联的阿秒超快过程。对相关问题的深入研究，有助于了解极端光场中物质微观动力学机理，为探索和操控原子分子内部阿秒尺度的电子运动及结构变化提供可借鉴的理论方案。

强激光场中的原子、分子电离是强场物理研究领域长期关注的核心物理过程之一。然而，随着阿秒科学的飞速发展，人们不断发现强场电离的已有物理图像并不完善，有时甚至与早期理论预言存在明显偏差，由此引发了新一轮的研究热潮。本项目围绕这一颇具争议的科研热点，综合运用量子从头计算方法和经典轨道分析，通过大规模数值模拟，结合最新实验发现，揭示了隧穿电离中的亚周期混沌散射及由此引发的超低能结构；研究了非序列双电离中的库仑三体问题、内壳层电子效应、关联电子超快热化，双色光时阈调控；提出多原子分子经典模型以解释多聚物中的里德堡电子囚禁及其对多聚物解离的影响；发展利用阿秒瞬态光吸收谱探测原子层面电子超快运动的新方法。这些结果一方面加深了人们对极端光场中物质微观动力学机理的理解，同时在超快科学、精密测量等领域也展现出了诱人的应用前景。在项目执行期间（2014-2016年），我们共发表相关SCI论文8篇，其中包括Physical Review Letters 3篇，Scientific Reports 1篇，Physical Review A 4篇,同时参与撰写专著一个章节，为相关领域的进一步深入研究提供了有益的参考。