Measuring the orbital angular momentum of electron vortex beams using a forked grating

TL;DR

This study experimentally demonstrates how electron vortex beams with orbital angular momentum diffract through a forked grating, enabling measurement of their OAM by analyzing diffraction patterns, which could improve electron beam characterization.

Contribution

It introduces a method using a forked grating and pinhole to measure the OAM of electron vortex beams, providing a new experimental approach.

Findings

Diffraction patterns become mirror asymmetric due to size differences.

OAM transfer occurs as nh after diffraction through the grating.

Forked grating with a pinhole can act as an OAM analyzer.

Abstract

The present study experimentally examines how an electron vortex beam with orbital angular momentum (OAM) undergoes diffraction through a forked grating. The nth-order diffracted electron vortex beam after passing through a forked grating with a Burgers vector of 1 shows an OAM transfer of nh. Hence, the diffraction patterns become mirror asymmetric owing to the size difference between the electron beams. Such a forked grating, when used in combination with a pinhole located at the diffraction plane, could act as an analyzer to measure the OAM of input electrons.