Talbot Interferometer for Free Electrons

We report the first demonstration of a Talbot interferometer for electrons, similar to ones that have been demonstrated for atoms. The interferometer was used to image the Talbot carpet formed by 2 keV-energy electrons behind a nano-fabricated material grating. The Talbot interferometer design uses two identical gratings, and is particularly sensitive to distortions of the incident wavefronts. To illustrate this we used our interferometer to measure a 2-meter radius of curvature for the wavefronts in a weakly focused electron beam.