Coherent regime of Kapitza-Dirac effect with electrons
Abstract
Electron matter waves coherently diffract when passing through a periodic structure of light formed by two interfering light waves. In this so-called Kapitza-Dirac effect, the electron momentum changes due to absorption and emission of photons via stimulated Compton scattering. Until now, the effect has only been observed with low energy electrons due to the small momentum of a visible photon compared to the momentum of high energy electron leading to diffraction angles of 10^(-4) rad or smaller. We report on the observation of the Kapitza-Dirac effect in a scanning electron microscope using high energy (20 keV and 30 keV) electrons with de-Broglie wavelengths of 9 pm and 7 pm, respectively. The photon sidebands in the electron transverse momentum spectrum are detected in the convergent beam diffraction geometry using spatial filtering. As the coupling strength between the electrons and the light field increases, the sideband populations exhibit coherent, reversible oscillations among diffraction orders. The effect can serve as a coherent electron beam-splitter or a phase-plate in various types of electron microscopes.
Keywords
Cite
@article{arxiv.2511.14508,
title = {Coherent regime of Kapitza-Dirac effect with electrons},
author = {Kamila Moriová and Petr Koutenský and Neli Laštovičková Streshkova and Marius Constantin Chirita Mihaila and Zbyněk Šobáň and Jaromír Kopeček and Andreas Schertel and Martin Kozák},
journal= {arXiv preprint arXiv:2511.14508},
year = {2025}
}
Comments
v1: preprint; licence: CC BY 4.0. Data necessary for replication of results are available in the Zenodo repository at https://doi.org/10.5281/zenodo.17614645