Electron-light interactions and the various mechanisms lying within this context have been discussed from the very early days of the rise of quantum mechanics. Transition from classical concepts such as Thomson scattering to more advanced quantum mechanical counterparts like Compton scattering, photoelectric effect, and more recently free-electron lasers, opened the way towards designing precise accelerating mechanisms and radiation sources.
Here, I first discuss electron-light interactions from the classical point of view. Mainly, inelastic interaction of electron beams with optical near-field distributions in nanostructures is considered. I show that near-field distributions can act as a mediator to transfer the energy between electron beams and light [1]. Moreover, based on the contribution of the electron-induced polarization to the radiation continuum, few-photon radiation sources are proposed and investigated [2]. Moreover, thin film electron-driven photon sources can be employed inside electron microscopes, for the purpose of spectral interferometry [3].
In a second part of my talk, I discuss electron-light interactions from semi-classical standpoint. First, I investigate the free-space interaction and consider the generalization of Kapitza-Dirac effect (KDE) to address quantum-coherent phenomena which occur as a result of interference between ponderomotive and absorptive/emissive parts of the minimal coupling Hamiltonian [4]. Then, I talk about the interaction of point-projection slow-electron wavepackets with light and nanostructures [5]. It is shown that the coupling strength between electrons and near-field light is increased by decreasing the electron velocity; hence this fact demonstrates the sensitivity of slow electrons to the electromagnetic interactions, covering both elastic and inelastic scattering.

References
[1] N Talebi, J. Opt. 19 (2017), 103001.
[2] N Talebi, S Meuret, S Guo, M Hentschel, A Polman, H Giessen, et al., Nat. Commun. 10 (2019), 599.
[3] N Talebi, Sci. Rep. 6 (2016), 33874.
[4] N Talebi and C Lienau, "Interference between Quantum Paths in Coherent Kapitza-Dirac Effect," New J. Phys. 21 (2019), 093016
[5] J Vogelsang, N Talebi, G Hergert, A Wöste, P Groß, A Hartschuh, et al., ACS Photon. 5 (2018), 3584.