Observation of Electron Energy Discretization in Strong Field Double Ionization

TL;DR

This paper reports the experimental observation of discrete energy structures in electrons emitted during strong field double ionization of Argon, revealing quantized energy levels consistent with quantum mechanical predictions.

Contribution

It provides the first experimental evidence of electron energy discretization in strong field double ionization, including ATI peaks in individual electron energies.

Findings

Discrete ATI peaks in sum electron energy

Observation of two ATI combs in individual electron energies

Agreement with quantum mechanical predictions

Abstract

We report on the observation of discrete structures in the electron energy distribution for strong field double ionization of Argon at 394 nm. The experimental conditions were chosen in order to ensure a non-sequential ejection of both electrons with an intermediate rescattering step. We have found discrete ATI (above-threshold ionization) like peaks in the sum energy of both electrons, as predicted by all quantum mechanical calculations. More surprisingly however is the observation of two ATI combs in the energy distribution of the individual electrons.