Symmetry-constrained electron vortex propagation

TL;DR

This paper investigates how geometrical symmetries influence the behavior of electron vortex beams, combining simulations and experiments to understand their interactions with symmetric apertures and effects on their orbital angular momentum and vortex structure.

Contribution

It introduces a symmetry-focused analysis of electron vortex beam interactions, providing new insights into their propagation and OAM stability.

Findings

Symmetry affects vortex beam propagation and OAM conservation.

Experimental and simulation results show vortex structure changes with aperture symmetry.

Insights could improve electron microscopy techniques.

Abstract

Electron vortex beams hold great promise for development in transmission electron microscopy, but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to focus on the interaction between geometrical symmetries, OAM and topology. We present multiple simulations, alongside experimental data to study the behaviour of a variety of electron vortex beams after interacting with apertures of different symmetries, and investigate the effect on their OAM and vortex structure, both in the far-field and under free-space propagation.