Probing Wigner time delays with photoelectron interferometry: Anisotropic long-range imprint of the short-range centrifugal potential

TL;DR

This paper develops an analytical approach to study two-photon ionization in hydrogen-like atoms, revealing how long-range effects influence photoelectron time delays and anisotropy, with implications for understanding ultrafast electron dynamics.

Contribution

It introduces an approximate expression for the long-range phase in two-photon ionization, combining asymptotic continuum eigenfunctions with perturbative methods to address anisotropy and soft-photon effects.

Findings

Analytic formalism captures long-range phase effects in two-photon ionization.

Describes anisotropic continuum-continuum photoionization time delays.

Applicable to soft-photon regimes and propensity rules.

Abstract

We consider the two-photon ionization of Hydrogen-like atoms. We find an approximate expression of the long-range phase based on an asymptotic expansion of the continuum eigenfunctions within the Wentzel-Kramers-Brillouin approximation. Combined with commonly used perturbative approaches, the resulting analytic formalism can treat, at the same time, the two-photon propensity rules, the anisotropy in the continuum-continuum photoionization time delay and the soft-photon regime.