Strong electron-photon interactions with high-Q microresonators

The main objective of the SEPhIM research action is the development and exploitation of strong electron-photon interactions with photonic-chip-based high-Q microresonators and photo-induced near-field electron microscopy (PINEM).

This will be achieved using the ultra-high quality factor of integrated microresonators to enhance the coupling strength between free electrons and cavity photons in an ultrafast transmission electron microscope (UTEM).

This project will bridge and separately advance the fields of integrated photonics, ultrafast electron microscopy, and quantum optics.By performing UTEM-PINEM, a multidimensional imaging and spectroscopy of the microresonators are available.

The enhanced electron-photon interaction, mediated by the high Q-factor of the microresonators, will lead to a strong phase modulation of free electrons, a wide spectral broadening of the electron energy, and the measurement of cavity-photon lifetime.

Moreover, using temporal dissipative solitons formed in the microresonators, time-gated electron-soliton interactions will also be investigated.

Due to the strong spatiotemporal confinement of the soliton pulse, the electron-photon coupling will be further enhanced.

Attosecond electron pulses in UTEM will enable time-domain electron microscopy of the soliton waveforms, while the concomitant generation of optical frequency combs will provide spectrally-resolved characterization of the electron-soliton interaction.

Furthermore, strong coupling between free electrons and cavity photons will enable quantum state synthesis and entanglement generation. As a proof-of-concept demonstration, we intend to perform all-optical non-demolition detection of free electrons.

The electron-photon interaction will be used to herald and register transmitted electrons, thus suppressing shot-noise in the electron beam.

This will improve the signal-to-noise ratio and reduce radiation damage in electron imaging and spectroscopy techniques.