Two-electron ionization in strong laser fields below intensity threshold: signatures of attosecond timing in correlated spectra

TL;DR

This paper presents an analytical model for correlated two-electron ionization in strong laser fields below the ionization threshold, revealing signatures of attosecond timing in the electron spectra.

Contribution

It introduces a nonperturbative analytical model that captures all relevant interactions in the deeply quantum regime of two-electron ionization.

Findings

Distinct signatures of electron-electron and electron-ion interactions in spectra

Insights into mutual electron dynamics during ionization

Model applicable to low-energy, strongly correlated regimes

Abstract

We develop an analytical model of correlated two-electron ionization in strong infrared laser fields. The model includes all relevant interactions between the electrons, the laser field, and the ionic core nonperturbatively. We focus on the deeply quantum regime, where the energy of the active electron driven by the laser field is insufficient to collisionally ionize the parent ion, and the assistance of the laser field is required to create a doubly charged ion. In this regime, the electron-electron and the electron-ion interactions leave distinct footprints in the correlated two-electron spectra, recording the mutual dynamics of the escaping electrons.