Ultrafast electron vortex produced by a grating made of light

TL;DR

This paper presents an all-optical method to generate electron vortices with tunable orbital angular momentum by diffracting electrons through a light-made grating, expanding possibilities in electron-based technologies.

Contribution

It introduces a novel all-optical technique for creating electron vortices using light-made gratings and stimulated Compton scattering, avoiding nanofabrication.

Findings

Successfully transferred orbital angular momentum to electrons via light diffraction.

The quantum number of angular momentum transfer can be tuned freely.

Method applicable to various charged particles, atoms, and molecules.

Abstract

The generation of vortex matter waves carrying quantized orbital angular momentum is challenging and relies heavily on the material nanofabrication methods due to their extremely small de-Broglie wavelengths. Here, we introduce an all-optical method for generating an electron vortex by diffraction through a grating made of light. We realize the orbital angular momentum transfer between free electrons and photons by stimulated Compton scattering. The transferred angular momentum quantum number can be freely tuned. The method can be generalized to a broad range of charged particles, neutral atoms, and molecules of diverse masses. Our results open up novel opportunities for applications in free electron lasers and ultrafast electron microscopy by utilizing the orbital angular momentum degree of freedom of free electrons.