Inelastic Electron Scattering at a Single-Beam Structured Light Wave

In this work we demonstrate the inelastic scattering of slow-electron wavepackets at a propagating Hermite-Gaussian light beam. The pulsed Hermite-Gaussian beam thereby forms a ponderomotive potential for the electron with large enough momentum components, leading to the inelastic scattering of electrons and their bunching along the longitudinal direction. We show that the resulting energy-gain spectra after the interaction is strongly influenced by the self-interference of the electron in this ponderomotive potential. It is shown that this effect is observable for various optical wavelengths and intensities and further discuss how the variation of the electron velocity and the light intensity allow to control the energy modulation of the electron wavepacket. This effect opens up a new platform for manipulating the electron wavepacket by utilizing the vast landscape of structured electromagnetic fields.