新型激光场下原子的二向色性和光场量子性研究

二向色性因在确定物质结构、揭示原子分子电离机制和表征激光场参数等方面中的应用而备受人们的关注。在不同偏振态的极紫外(XUV)和红外(IR)新型激光场调控下，原子电离动力学过程中的二向色性研究还处在起步阶段，针对二向色性中的库仑效应和光场量子性问题还未见报道。申请人前期研究了原子在线偏振新型激光场下的阈上电离过程，发现了XUV激光场的量子性的线索。基于前期工作和热点问题，本项目将采用光场量子化的频域理论研究原子在线/圆偏振新型激光场下电离动力学过程中的二向色性和光场量子性。分析库仑效应在二向色性中的作用：解释光电子能谱低能结构的形成原因，阐明大角度出射光电子对二向色性的贡献；揭示在电离过程中光场的量子性。本项目的研究将有助于从全量子角度理解新型激光场中原子电离过程中的二向色性，完善产生二向色性的物理机制，为原子在新型激光场中电离过程的实验研究提供理论支持。

The application of the atomic dichroism provides an effective tool to determine material structures, reveal the ionization dynamics and characterize laser parameters, which has attracted more and more attention. Under the new extreme ultraviolet (XUV) and infrared (IR) laser fields, the investigation of the atomic dichroism in the ionization dynamics is still immature, the Coulomb effect and quantum property of lasers in dichroism have not been reported so far. We have studied the atomic ionization process in the linearly polarized XUV+IR two-color laser fields, and found that the quantum effect of XUV laser field exists in the ionization spectrum. Based on previous work and hot issues, this proposal will study the dichroism and quantum effect in the ionization dynamics of atoms exposed to the XUV+IR linearly/circularly polarized two-color laser fields based on frequency-domain theory. The role of Coulomb effect in the atomic dichroism will be analyzed: explain the formation of low-energy structure in photoelectron spectra and illustrate the contributions of the ionized electron with the larger angles to dichroism. The quantum effect of different polarization XUV laser field in the ionization process will be revealed. This project will be helpful to further understand the dichroism in the atomic ionization process from the full quantum perspective, and improve the physical mechanism of dichroism, which provides theoretical support for the experimental study of atomic ionization process in the XUV+IR laser field.