报告时间：2019年9月19日 8:30-9:30

报告地点：H124

报告摘要：A recent ultrafast pump-probe technique has allowed measurement of time delays during photoemission in a variety of systems ranging from atoms and molecules to solids with unprecedented temporal resolution. However, identifying the underlying physics is still a challenge especially in complicated multichannel above-threshold ionization (ATI) experiments. Here we demonstrate that the time delays of different ionization pathways in ATI can be clearly resolved and extracted with a semiclassical statistical method. The remarkable phase shift of near threshold photoelectrons can be attributed to a temporary retrapping of a photoelectron by the atomic potential in quasibound states after emerging in the continuum state. This continuum-bound-continuum scattering manifests as a new resonant effect in strong-field photoemission. Our results unify the seemingly opposing quantum Eisenbud-Wigner-Smith time delay and classical Coulomb-induced time delay by highlighting the same physical picture, which holds promise for an intuitive interpretation of time-resolved fundamental electronic processes in strong-field experiments and epistemological reexamination of the quantum-classical correspondence.

REFERENCES:

[1] Xiaochun Gong, Cheng Lin, Feng He, Qiying Song, Kang Lin, Qinying Ji, Wenbin Zhang, Junyang Ma, Yunquan Liu, Heping Zeng, Weifeng Yang* and Jian Wu*, Phys. Rev. Lett. 118, 143203 (2017).

[2] Xiaohong Song, Guangluo Shi, Guojun Zhang, Jingwen Xu, Cheng Lin, Jing Chen* and Weifeng Yang*, Phys. Rev. Lett. 121, 103201 (2018).

报告人简介：杨玮枫

汕头大学卓越计划拔尖层次特聘教授、博士生导师，广东省物理学会理事会理事，广东省“先进光学与光电子学”创新团队负责人，教育部大学物理教学指导委员会中南地区工作委员，汕头市科技创新领军人才，汕头大学物理系主任，先进光学与光电子学研究中心主任。从事激光光电子学研究。以第一作者/通讯作者在重要国际SCI学术刊物发表高质量学术论文三十余篇，（其中包括物理学顶级学术期刊Physical Review Letters 3篇); H因子为14，单篇SCI刊源引用超过80次。多次应邀在国内外重要学术会议作特邀报告。部分研究成果得到国际著名同行科学家的高度评价与引用。2008年入选上海市科技启明星计划， 2009年获全国优秀博士学位论文奖， 2012年入选广东省“千百十工程”省级培养对象，2013年入选广东省“扬帆计划”引进紧缺拔尖人才。先后主持和承担包括三项国家自然科学基金、广东省创新团队（自然科学）项目和广东省自然科学基金重点项目在内的科研项目十余项，现研究组在研项目经费500余万。国家自然科学基金通讯评审专家，国际著名SCI刊物ACS Photonics, Opt. Lett., Opt. Express, New J. Phys.等的特邀审稿专家。