Mapping the direction of electron ionization to phase delay between VUV and IR laser pulses

TL;DR

This paper presents a theoretical method to map electron ionization direction to phase delay between VUV and IR laser pulses, enabling control over electron trajectories and potential nanoscale magnetic field generation.

Contribution

It introduces a novel theoretical framework linking phase delay to electron emission direction using quantum and classical techniques.

Findings

One-to-one mapping between ionization direction and phase delay.

Method to produce nanoscale ring currents and magnetic fields.

Accurate quantum mechanical modeling of molecular continuum states.

Abstract

We theoretically demonstrate a one-to-one mapping between the direction of electron ionization and the phase delay between a linearly polarized VUV and a circular IR laser pulse. To achieve this, we use an ultrashort VUV pulse that defines the moment in time and space when an above threshold electron is released in the IR pulse. The electron can then be accelerated to high velocities escaping in a direction completely determined by the phase delay between the two pulses. The dipole matrix element to transition from an initial bound state of the N$_2$ molecule, considered in this work, to the continuum is obtained using quantum mechanical techniques that involve computing accurate continuum molecular states. Following release of the electron in the IR pulse, we evolve classical trajectories, neglecting the Coulomb potential and accounting for quantum interference, to compute the distribution of the direction and magnitude of the final electron momentum. The concept we theoretically develop can be implemented to produce nanoscale ring currents that generate large magnetic fields.