Electron-atom scattering in a circularly polarized laser field

TL;DR

This paper analyzes high-energy electron-atom scattering in a circularly polarized laser field using perturbation theory, revealing that the nonlinear differential cross sections are independent of the laser's dynamical phase and helicity.

Contribution

It introduces a theoretical framework for electron-atom scattering in circularly polarized laser fields, showing invariance of cross sections to certain laser parameters, and compares with linear polarization results.

Findings

Nonlinear differential cross sections are independent of the dynamical phase.

Cross sections do not depend on the helicity of the circularly polarized laser.

Relations to linear polarization results are established.

Abstract

We consider electron-atom scattering in a circularly polarized laser field at sufficiently high electron energies, permitting to describe the scattering process by the first order Born approximation. Assuming the radiation field has sufficiently moderate intensities, the laser-dressing of the hydrogen target atom in its ground state will be treated in second order perturbation theory. Within this approximation scheme, it is shown that the nonlinear differential cross sections of free-free transitions do neither depend on the {\it dynamical phase} $\phi$ of the radiative process nor on the {\it helicity} of the circularly polarized laser light. Relations to the corresponding results for linear laser polarization are established.