Phase-locking mechanism in non-sequential double ionization

TL;DR

This paper uncovers a phase-locking mechanism in strong laser field double ionization, showing how laser phase and electron trajectories interact to influence ionization yields and quantum entanglement, with control via laser chirp.

Contribution

It introduces a new phase-locking mechanism in non-sequential double ionization and demonstrates control of ionization and entanglement through laser frequency chirp.

Findings

Laser phase causes injection locking of electron trajectories.

Ionization yields are affected by laser intensity in the knee region.

Laser chirp enables control over electron entanglement.

Abstract

Here, we identify a new mechanism where the early stage of electron ionization in the field of strong femtosecond laser pulse determines the final yield of non-sequential double ionization. By using simple trajectory methods we prove that the powerful short wavelength laser field causes an injection locking between its phase and the phases of the electron trajectories, which is next responsible for the enhanced or suppressed ionization for given intensities in the knee region. It is shown that both ionization and entanglement of the final electron state can be easily controlled by introducing frequency chirp of the laser field. Our methods allow one to quantify the quantum correlations due to the different mechanisms of strong field ionization.