Carrier-envelope-phase and helicity control of electron vortices in photodetachment

TL;DR

This paper demonstrates how the carrier-envelope phase and helicity of ultrashort laser pulses can be used to control electron vortices and momentum spirals in photodetachment of H$^-$, providing new tools for field characterization.

Contribution

It introduces a method to actively manipulate and control electron vortex patterns in photodetachment using CEP and pulse helicity, revealing their relation to laser field symmetry.

Findings

Vortical patterns can be rotated in the polarization plane by changing CEP.

Spiral formation and vortex annihilation relate to the laser field's time-reversal symmetry.

Control of electron vortices offers new insights into laser-matter interactions.

Abstract

Formation of electron vortices and momentum spirals in photodetachment of the H$^-$ anion driven by isolated ultrashort laser pulses of circular polarization or by pairs of such pulses (of either corotating or counterrotating polarizations) are analyzed under the scope of the strong-field approximation. It is demonstrated that the carrier-envelope phase (CEP) and helicity of each individual pulse can be used to actively manipulate and control the vortical pattern in the probability amplitude of photodetachment. Specifically, the two-dimensional mappings of probability amplitude can be rotated in the polarization plane with changing the CEP of the driving pulse (or two corotating pulses); thus, offering a new tool of field characterization. Furthermore, it is shown that the formation of spirals or annihilation of vortices relates directly to the time-reversal symmetry of the laser field, which is realized by a pair of pulses with opposite helicities and CEPs.