Cavity mediated electron-photon interaction

Guanhao Huang
EPFL, Switzerland

Advancing quantum information, communication and sensing relies on the generation and control of quantum correlations in complementary degrees of freedom. Here, we demonstrate both the stimulated phase-matched interaction and the spontaneous inelastic scattering of free electrons with the evanescent field of a photonic-chip-based optical microresonator.
Stimulated phase matched interaction leads to efficient electron–light scattering at extremely low, continuous-wave optical powers, establishes a framework for enhanced electron beam control in the context of laser phase plates, beam modulators and continuous-wave attosecond pulse trains, resonantly enhanced spectroscopy and dielectric laser acceleration.
Spontaneous inelastic scattering produces intracavity photons correlated with energy-shifted electrons. This parametric pair-state preparation will underpin the future development of free-electron quantum optics, providing a pathway to quantum-enhanced imaging, electron-photon entanglement, and heralded single-electron and Fock-state photon sources.

References:
Henke, et al. Nature 600, 653–658 (2021). Feist, et al. arXiv:2202.12821 (2022).