报告人：陈京，北京应用物理与计算数学研究所研究员。
报告人简介：
陈京，北京应用物理与计算数学研究所研究员。1992年毕业于中国科学技术大学近代物理系。1999年在中国工程物理研究院获理学博士学位。1999年至2001年在中科院理论物理研究所做博士后。2001-2004年先后在韩国高等科学技术研究院和美国堪萨斯大学从事访问研究工作。2005年进入北京应用物理与计算数学研究所工作。主要从事强激光场与原子分子相互作用的理论研究，通过与国内强场原子分子实验小组紧密合作，对原子分子电离、里德堡态激发和高次谐波产生等动力学过程进行了全面系统的研究，在国内外学术期刊上发表论文150余篇。研究成果分别入选国家十一五期间重大基础研究进展、2012年中国高等学校十大科技进展和2013年中国光学重要成果。主持和参加国家自然科学基金项目、国家973项目、国家863项目、科技部重点专项和中物院科学技术基金重大项目等科研项目十余项。2014年获得国家杰出青年基金。2015年入选国家百千万人才工程并获得“有突出贡献中青年专家”称号。2016年获国务院政府特殊津贴。2018年入选中国工程物理研究院“杰出专家”。
摘要：We propose a quantum model based on the S-matrix theory to study the Rydberg state excitation (RSE) process in intense infrared laser field. In this model, the electron is at first pumped into continuum state by the laser field and then evolves in the external field. Most of the ionized electrons come out as free electrons (above-threshold ionization), however, some of the electrons may be captured in the Rydberg states. The second-order term of the S-matrix expansion well reproduces the intensity dependence of the RSE in 800 nm laser field obtained by numerical solution of time-dependent Schrödinger equation which shows two series of high and low peak structures depending on parties of the ground and Rydberg states involved. The probability of the capture process strongly depends on the relative phase of different quantum orbits, resulting in the peak structure in the intensity dependence of the RSE process. Experimental results with 800 nm laser field for Xe and Ar are in good agreement with our model calculation. The third-order term of the S-matrix expansion which takes into account the collision between the electron and the ionic potential before the capture process can well reproduce the TDSE and experimental results for longer wavelength, i. e., 1800 nm which shows an oscillation structure with period of 50 TW/cm2. Analysis shows that the coherent superposition of the contributions of such trajectories with different travel times (each generating one of the various low-energy structure peaks) causes the oscillation in the intensity dependence of the RSE yield, which is especially noticeable for longer wavelengths. Our work provides a new picture of the RSE in intense laser field: a coherent recapture process accompanying the above-threshold ionization.
报告时间：2021年9月8日（周三）10:30
报告地点：生命科学楼504会议室
