Nanophotonic engineering of interactions between free electrons and light-matter systems

A hallmark of nanophotonics is the design of nanostructured materials (metasurfaces, photonic crystals, nanoresonators, etc.) to tailor the interaction of light with matter, either by shaping light propagation at the nanoscale, or by controlling emission from atoms and molecules. Recent developments in electron microscopy have generated a new wave of interest in studying interactions between electron beams and photonic modes [1], as well as electron beams and two-level systems (TLS) [2, 3].



In this talk, I will show how one can enhance and tailor interactions between free electrons and light-matter systems, such as photons in nanophotonic structures, and TLS embedded in cavities. Specifically, I will present a framework to model, tailor, enhance, and even optimize coupling and subsequent radiation from free electrons interacting with nanophotonic structures. I will present recent experimental efforts in demonstrating nanophotonic enhancement of coherent [4] and incoherent [5] cathodoluminescence, as well as quantum sensing of electron beams with color centers [3]. I will also show how this framework can inform the design of nanophotonic structures that can (1) reach the regime of strong coupling between single free electrons and photonic modes by ponderomotive guiding in a photonic microfiber, potentially enabling the realization of heralded macroscopic nonclassical light generation [6]; and (2) enhance coupling between free electrons and TLS, with potential applications in nanoscale quantum sensing [7, 8].





[1] Roques-Carmes et al., Applied Physics Reviews (2023)

[2] Gover et al., Physical Review Letters (2020)

[3] Catanzaro et al., Conference on Lasers and Electro-Optics (2024)

[4] Yang, Roques-Carmes, et al., Nature (2023)

[5] Roques-Carmes, Rivera, et al., Science (2022)

[6] Karnieli, Roques-Carmes, et al., ACS Photonics (2024)

[7] Grzesik, Roques-Carmes, Karnieli, et al., in preparation (2025)

[8] Karnieli, Tsesses, et al., Science Advances (2023)