An electron Talbot interferometer

TL;DR

This paper reports the first observation of the electron Talbot effect using a nanofabricated grating, demonstrating a new electron interferometry technique that maps near-field interference patterns and measures wavefront curvature.

Contribution

It introduces the first electron Talbot interferometer, extending Talbot effect observations to electrons and enabling sensitive wavefront measurements.

Findings

Successfully mapped the electron Talbot carpet behind a nanograting.

Used the interferometer to measure electron wavefront curvature.

Demonstrated potential applications in electron wavefront sensing.

Abstract

The Talbot effect, in which a wave imprinted with transverse periodicity reconstructs itself at regular intervals, is a diffraction phenomenon that occurs in many physical systems. Here we present the first observation of the Talbot effect for electron de Broglie waves behind a nanofabricated transmission grating. This was thought to be difficult because of Coulomb interactions between electrons and nanostructure gratings, yet we were able to map out the entire near-field interference pattern, the "Talbot carpet", behind a grating. We did this using a Talbot interferometer, in which Talbot interference fringes from one grating are moire'-filtered by a 2nd grating. This arrangement has served for optical, X-ray, and atom interferometry, but never before for electrons. Talbot interferometers are particularly sensitive to distortions of the incident wavefronts, and to illustrate this we used our Talbot interferometer to measure the wavefront curvature of a weakly focused electron beam. Here we report how this wavefront curvature demagnified the Talbot revivals, and we discuss applications for electron Talbot interferometers.