Exploiting lens aberrations to create electron vortex beams

TL;DR

This paper introduces a novel method for generating electron vortex beams by manipulating lens aberrations in a transmission electron microscope, combining theoretical modeling with experimental validation.

Contribution

It presents a new technique that uses controlled lens aberrations and specific alignments to produce electron vortex beams, demonstrated experimentally and supported by simulations.

Findings

Successful experimental demonstration of vortex beam creation.

Good agreement between experimental results and simulations.

New method leverages existing microscope components for beam generation.

Abstract

A model for a new electron vortex beam production method is proposed and experimentally demonstrated. The technique calls on the controlled manipulation of the degrees of freedom of the lens aberrations to achieve a helical phase front. These degrees of freedom are accessible by using the corrector lenses of a transmission electron microscope. The vortex beam is produced through a particular alignment of these lenses into a specifically designed astigmatic state and applying an annular aperture in the condensor plane. Experimental results are found to be in good agreement with simulations.