Role of the Coulomb potential on the ellipticity in atomic high-order harmonics generation

TL;DR

This paper investigates how the Coulomb potential influences the ellipticity of high-order harmonics generated in atoms under elliptically polarized lasers, revealing its contribution to harmonic ellipticity especially at low orders and short quantum paths.

Contribution

It introduces an analytical approach using the strong-field eikonal-Volkov approximation to analyze Coulomb effects on harmonic ellipticity, highlighting the symmetry break in the continuum state.

Findings

Coulomb potential affects harmonic ellipticity at low orders

Ellipticity arises from symmetry breaking in the continuum state

Analysis uses strong-field eikonal-Volkov approximation

Abstract

The role of the Coulomb potential on the generation of elliptically polarized high-order harmonics from atoms driven by elliptically polarized laser is investigated analytically. It is found that the Coulomb effect makes a contribution to the harmonic ellipticity for low harmonic orders and short quantum path. By using the strong-field eikonal-Volkov approximation, we analyze the influence of the Coulomb potential on the dynamics of the continuum state and find that the obtained harmonic ellipticity in our simulation originates from the break of symmetry of the continuum state.