Angular distributions in two-colour two-photon ionization of He

TL;DR

This paper uses advanced R-Matrix with time dependence calculations to study how angular distributions of helium ionized by two-color laser pulses depend on atomic structure details, comparing results with experimental data.

Contribution

It introduces a detailed RMT modeling approach to analyze anisotropy parameters in two-photon helium ionization, highlighting the impact of atomic structure inclusion.

Findings

Good agreement between theory and experiment for anisotropy parameters

Atomic structure complexity significantly affects angular distribution predictions

RMT effectively models two-photon ionization dynamics

Abstract

We present R-Matrix with time dependence (RMT) calculations for the photoionization of helium irradiated by an EUV laser pulse and an overlapping IR pulse with an emphasis on the anisotropy parameters of the sidebands generated by the dressing laser field. We investigate how these parameters depend on the amount of atomic structure included in the theoretical model for two-photon ionization. To verify the accuracy of the RMT approach, our theoretical results are compared with experiment.