Above-threshold ionization in a bicircular field: quantum orbits unfolding in a plane

25th Annual International Laser Physics Workshop

Becker, W.^1,2 ; Miloevi, D.B.^1,3,4

Max-Born-Institut, Max-Born-Str. 2a, Berlin

12489, Germany^1

National Research Nuclear University MEPhI, Kashirskoe Shosse 31, Moscow

115409, Russia^2

Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, Sarajevo

71000, Bosnia and Herzegovina^3

Academy of Sciences and Arts of Bosnia and Herzegovina, Bistrik 7, Sarajevo

71000, Bosnia and Herzegovina^4

关键词: Above-threshold ionization;    Angle-resolved;    Circularly polarized;    Counter rotating;    Frequency ratios;    Quantum orbits;    Spin asymmetry;    Strong-field approximations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/826/1/012008/pdf
DOI  :  10.1088/1742-6596/826/1/012008

来源: IOP

【 摘 要 】

Above-threshold ionization (ATI) of atoms by a strong bicircular laser field is investigated using the strong-field approximation and the quantum-orbit theory. The bicircular field consists of two coplanar counterrotating circularly polarized fields with a frequency ratio of 2:1. The velocity map of the angle-resolved ATI spectra, both for direct and rescattered electrons, reflects the shape of a parametric plot of the bicircular field and its symmetries. It is shown that the main characteristics of the ATI spectra can be explained using only a few quantum orbits having short travel times. We also analyze a recently discovered [Phys. Rev. A 93, 052402(R) (2016)] bicircular-field-induced spin asymmetry of the ATI electrons and show that the momentum dependence of the spin-asymmetry parameter is stronger for longer wavelengths.