强激光场原子隧穿电离中里德堡电子动力学研究

Many non-perturbative complex dynamical phenomena have been observed during the interaction between the ultra-intense laser field and atoms, including ionization above threshold, high-order harmonics generation, and the stabilization of atoms. Exploring the mechanism underlying these phenomena will provide the basic knowledge of the physical processes under the influence of ultra-intense laser field, and is of great importance for practical applications such as laser constraint fusion. Interestingly, recent studies suggested that the Rydberg electrons after tunneling in the intense field play a crucial role during the non-perturbative processes, especially in these novel phenomena recently reported, such as tunneling without ionization, acceleration of neutral atoms, and aggregation of meV electrons. Based upon the quantum mechanics and the latest experiment results, this project aims to comprehensively study the dynamics of Rydberg electrons during tunneling ionization by developing the semi-classical trajectory simulation method. First, the project will analyze the distribution of energy and angular momentum of Rydberg electrons, and then investigate the dependence of the yield of neutral atoms on the laser parameters as well as atom species. Second, our project will further study the impact of Rydberg electrons to the acceleration of neutral atoms, and then elucidate their contribution to the aggregation of meV electrons. The research on these issues related with Rydberg electrons during tunneling ionization will not only help us understand the atom ionization mechanism and the microscopic dynamics of matter in intense laser field, but also promote the development of new technologies such as the manipulation of atoms and molecules.

强激光场与原子的相互作用会引发大量的非微扰效应。理解这些效应是认识强激光场与物质相互作用的基础，对实现包括激光约束聚变在内的各种应用具有重要意义。最近，在强激光场原子隧穿电离区观察到里德堡原子的残存、中性原子的加速和毫电子伏特（meV）能量电子的聚集等一些新的非微扰现象。在这些现象里，原子隧穿电离过程中产生的里德堡电子起了关键作用。本项目将基于量子力学，发展半经典方法等理论手段，研究强场隧穿电离中里德堡电子的动力学过程，分析里德堡电子的能量与角动量分布，给出里德堡原子的产率对激光参数和原子种类的依赖关系。在此基础上，进一步研究激光场对中性原子的加速效应，并阐明里德堡电子对 meV 能量电子的贡献。本项研究，有助于加深对强场中原子电离机制的理解，提高对原子稳定化和阈上电离等问题的认识，深化对强激光场中物质微观动力学的研究，并为原子分子操控等相关技术的发展提供理论支持。

强激光场与原子的相互作用会引发大量的非微扰效应。理解这些效应是认识强激光场与物质相互作用的基础，对各种实际应用具有重要意义。本项目基于量子力学，发展了求解薛定谔方程的数值解法，建立了研究非偶极相互作用下的半经典光电离模型，实现了利用半经典方法对强场隧穿电离的量子相干效应的研究。我们的主要研究内容包括：1）光压对光电子动量的影响；2）隧穿电离光电子的低能结构；3）利用垂直双色光实现对电子关联的操控研究；4）椭偏光场中隧穿电离的非绝热效应。通过本项目的执行，我们加深了对强场原子电离机制的理解，提高了对阈上电离等问题的认识，深化了强激光场中物质微观动力学的研究，并为原子分子操控等相关技术的发展提供了理论支持。