Ultrafast Kapitza-Dirac effect

• 成果类型: Article
• 署名作者: Lin, Kang; Eckart, Sebastian; Liang, Hao; Hartung, Alexander; Jacob, Sina; Ji, Qinying; Schmidt, Lothar Ph. H.; Schoeffler, Markus S.; Jahnke, Till; Kunitski, Maksim; Doerner, Reinhard
• 署名单位: Zhejiang University; Goethe University Frankfurt; Max Planck Society; Shanghai Jiao Tong University; Max Planck Society
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12668
• DOI: 10.1126/science.adn1555
• 发表日期: 2024-03-29
• 页码: 1467-1470
• 关键词: scattering; electrons; light; atoms

摘要

Similar to the optical diffraction of light passing through a material grating, the Kapitza-Dirac effect occurs when an electron is diffracted by a standing light wave. In its original description, the effect is time independent. Here, we extended the Kapitza-Dirac effect to the time domain. By tracking the spatiotemporal evolution of a pulsed electron wave packet diffracted by a 60-femtosecond (where one femtosecond = 10(-15) seconds) standing wave pulse in a pump-probe scheme, we observed time-dependent diffraction patterns. The fringe spacing in the observed pattern differs from that generated by the conventional Kapitza-Dirac effect. By exploiting this time-resolved diffraction scheme, we can access the time evolution of the phase properties of a free electron and potentially image ionic potentials and electronic decoherences.