Ionization of co- and counter-rotating electrons in ultrashort circularly polarized laser pulses

We have studied ionization of atoms with non-zero orbital angular momentum by an intense circularly polarized laser as a function of wavelength [1,2]. Numerical solutions of the time-dependent Schrodinger equation show a change by two orders of magnitude in the emission probability of counter- over co-rotating electrons in the few-photon ionization regime due to differences in the accessible ionization pathways and intermediate resonances. To gain further insights, we use time independent Floquet formalism to determine the dependence of the ionization probabilities on Stark resonances associated with the magnetic quantum number of an initial state. This provides a prediction of the maximum degree of orbital polarization in terms of single active electron parameters.

[1] S. Walker, L. Kolanz, J. Venzke, and A. Becker, Phys. Rev. A 103, L061101 (2021).

[2] S. Walker, L. Kolanz, J. Venzke, and A. Becker, Phys. Rev. Research 3, 043501 (2021).