Electron-photon pair states generated at a silicon nitride integrated photonics microresonator

Abstract

Advancing quantum information and communication requires the control of quantum correlations in complementary degrees of freedom. In this work, we generate electron-photon pair states via inelastic scattering of free electrons at a high-Q photonic-chip-based microresonator. In analogy to spontaneous parametric down-conversion, time-and energy-resolved detection of both particles enables various heralding schemes. We experimentally characterize this new heralded source of single photons and free electrons. Ultimately, these results underpin the recent progress in free-electron quantum optics, promising electron-photon entanglement, tailored photon Fock states, and quantum-enhanced electron imaging.