Resonant sequential two-photon ionization of atoms by twisted and plane-wave light

TL;DR

This paper investigates how twisted and plane-wave light influence the ionization process of sodium atoms, focusing on angular distributions and circular dichroism within a relativistic framework, revealing strong dependence on beam geometry.

Contribution

It provides a detailed analysis of the effects of twisted light parameters and geometry on two-photon ionization, a novel study in the relativistic regime.

Findings

Dependence of ionization characteristics on twisted light parameters is strongest when beams are perpendicular.

The study offers insights into controlling photoelectron angular distributions via beam geometry.

Relativistic effects are significant in the ionization process with twisted light.

Abstract

We study the resonant sequential two-photon ionization of neutral atoms by a combination of twisted- and plane-wave light within a fully relativistic framework. In particular, the ionization of an isotropic ensemble of neutral sodium atoms ($Z = 11$) from their ground $3^{2}S_{1/2}$ state via the $3^{2}P_{3/2}$ level is considered. We investigate in details the influence of the kinematic parameters of incoming twisted radiation on the photoelectron angular distribution and the circular dichroism. Moreover we study the influence of the geometry of the process on these quantities. This is performed by changing the propagation directions of the incoming twisted and plane-wave light. It is found that the dependence on the kinematic parameters of the twisted photon is the strongest if the plane-wave and twisted light beams are perpendicular to each other.