Circular dichroism in free-free transitions of high energy electron-atom scattering

TL;DR

This paper investigates how circular dichroism manifests in high-energy electron-hydrogen scattering within a combined laser field, revealing observable effects in two-photon transitions through second-order perturbation theory.

Contribution

It demonstrates the possibility of observing circular dichroism in both differential and integrated cross sections in high-energy scattering with a specific laser configuration, including bound-continuum state coupling.

Findings

Circular dichroism appears in two-photon transitions under combined laser fields.

Dichroism is observable in both differential and integrated cross sections.

Second-order perturbation theory captures the laser-dressing effects on the atom.

Abstract

We consider high energy electron scattering by hydrogen atoms in the presence of a laser field of moderate power and higher frequencies. If the field is a superposition of a linearly and a circularly polarized laser beam in a particular configuration, then we can show that circular dichroism in two photon transitions can be observed not only for the differential but also for the integrated cross sections, provided the laser-dressing of the atomic target is treated in second order perturbation theory and the coupling between hydrogenic bound and continuum states is involved.