Generation of vortex electrons by atomic photoionization

TL;DR

This paper investigates how twisted light can transfer orbital angular momentum to electrons during atomic ionization, revealing conditions for generating vortex electrons and analyzing the effects of atomic positioning and target size.

Contribution

It introduces a detailed theoretical analysis of OAM transfer in atomic photoionization, including effects of atom position and target size, expanding understanding of vortex electron generation.

Findings

Electron OAM is definite when atom is on photon axis.

Electron wave packet size depends on photon energy.

Atom displacement causes OAM dispersion.

Abstract

We explore the process of orbital angular momentum (OAM) transfer from a twisted light beam to an electron in atomic ionization within the first Born approximation. The characteristics of the ejected electron are studied regardless of the detection scheme. We find that the outgoing electron possesses a definite projection of OAM when a single atom is located on the propagation axis of the photon, whereas the size of the electron wave packet is determined solely by the energy of the photon rather than by its transverse coherence length. Shifting the position of the atom yields a finite dispersion of the electron OAM. We also study a more experimentally feasible scenario - a localized finite-sized atomic target - and develop representative approaches to describing coherent and incoherent regimes of photoionization.