Optical vortices discern attosecond time delay in electron emission from magnetic sublevels

TL;DR

This paper demonstrates that optical vortex pulses can measure attosecond time delays in electron emission from magnetic sublevels, revealing strong angular and spatial dependencies, and enabling high-resolution spatio-temporal magnetic sensing.

Contribution

It introduces a novel method using optical vortices to measure attosecond delays from magnetic sublevels, even in spherically symmetric targets, with high spatial resolution.

Findings

Significant attosecond time delays depend on magnetic sublevels.

Strong angular dependence of the measured delays.

Atomic-scale variation in delays based on orbital position.

Abstract

Photoionization from energetically distinct electronic states may have a relative time delay of tens of attoseconds. Here we demonstrate that pulses of optical vortices allow measuring such attoseconds delays from magnetic sublevels, even from a spherically symmetric target. The difference in the time delay is substantial and exhibits a strong angular dependence. Furthermore, we find an atomic scale variation in the time delays depending on the target orbital position in the laser spot. The findings offer thus a qualitatively new way for a spatio-temporal sensing of the magnetic states from which the photoelectrons originate, with a spatial resolution way below the diffraction limit of the vortex beam. Our conclusions follow from analytical considerations based on symmetry, complemented and confirmed with full numerical simulations of the quantum dynamics.