Probing Nanoscale Optical Fields and Phase-Shaping Electron Beams by Inelastic Electron-Light Scattering

Ultrafast transmission electron microscopy (UTEM) is a powerful tool to study the dynamics of nanoscale systems, combining the versatile imaging, diffraction and spectroscopy capabilities of state-of-the-art TEM with femtosecond temporal resolution of a laser pump/electron probe scheme [1,2]. In particular, inelastic scattering between a free electron pulse and strong optical near fields [3,4] (Fig.1a) allows for a coherent manipulation of the electron quantum state. In this mechanism, the optical field imprints a sinusoidal phase modulation on the electron wave function [4], which manifests in a comb of photon sidebands in the kinetic energy distribution (Fig.1b) and — by energy-filtering — enables photon-induced near-field electron microscopy (PINEM) [3].