Helicity-dependent time delays in multiphoton ionization by two-color circularly polarized laser fields

• Published in: Frontiers of physics 2021-10, Vol.16 (5), p.52503, Article 52503
• Main Authors: Ke, Qing-Hua, Zhou, Yue-Ming, Liao, Yi-Jie, Liang, Jin-Tai, Zhao, Yong, Tan, Jia, Li, Min, Lu, Pei-Xiang
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; Circular polarization; Color; Condensed Matter Physics; Helicity; helicity-dependent time delay; Hydrogen; Hydrogen atoms; Ionization; Lasers; Molecular; multiphoton ionization; Optical and Plasma Physics; Particle and Nuclear Physics; Photoelectrons; Photon absorption; Photons; Physics; Physics and Astronomy; Research Article; Rotation; Schrodinger equation; Sidebands; TCCP; Time dependence; Time lag
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-021-1084-7

By numerically solving the three-dimensional time-dependent Schrödinger equation, we have invest-tigated multiphoton ionization of hydrogen atom in the two-color circularly polarized (TCCP) laser fields consisting of a strong 400 nm and a much weaker 800 nm pulses. Due to the presence of perturb-bative 800 nm laser pulse, sideband peaks emerge between the above-threshold ionization rings in the photoelectron momentum distributions. Our numerical results show that the sideband peaks exhibit one-lobe structure in the co-rotating TCCP laser fields, while it displays the three-lobe structure in the counter-rotating TCCP laser fields. Moreover, the photoelectron yield of sidebands in the co-rotating TCCP fields is much higher than those of the counter-rotating TCCP fields. These phenomena could be well explained from the perspective of the photon-absorption channels via the selection rules. In-terestingly, an obvious phase shift between the sidebands of different orders from the co-rotating and counter-rotating TCCP fields is observed. This shift indicates the helicity-dependent time delay in the one-photon continuum-continuum transition process.