Recollisions and correlated double ionization with circularly polarized light

TL;DR

This paper demonstrates that recollision can significantly enhance double ionization in circularly polarized laser fields, challenging the belief that such recollisions are suppressed, and explains experimental discrepancies using a classical model.

Contribution

It reveals that recollision effects are substantial in circular polarization, providing a classical explanation for experimental differences in helium and magnesium ionization.

Findings

Recollision enhances double ionization even with circular polarization.

A classical model explains the presence or absence of the knee in experiments.

Recollision effects are significant contrary to previous assumptions.

Abstract

It is generally believed that the recollision mechanism of atomic nonsequential double ionization is suppressed in circularly polarized laser fields because the returning electron is unlikely to encounter the core. On the contrary, we find that recollision can and does significantly enhance double ionization, even to the extent of forming a "knee", the signature of the nonsequential process. Using a classical model, we explain two apparently contradictory experiments, the absence of a knee for helium and its presence for magnesium.