---
res:
  bibo_abstract:
  - 'When impinging on optical structures or passing in their vicinity, free electrons
    can spontaneously emit electromagnetic radiation, a phenomenon generally known
    as cathodoluminescence. Free-electron radiation comes in many guises: Cherenkov,
    transition, and Smith–Purcell radiation, but also electron scintillation, commonly
    referred to as incoherent cathodoluminescence. While those effects have been at
    the heart of many fundamental discoveries and technological developments in high-energy
    physics in the past century, their recent demonstration in photonic and nanophotonic
    systems has attracted a great deal of attention. Those developments arose from
    predictions that exploit nanophotonics for novel radiation regimes, now becoming
    accessible thanks to advances in nanofabrication. In general, the proper design
    of nanophotonic structures can enable shaping, control, and enhancement of free-electron
    radiation, for any of the above-mentioned effects. Free-electron radiation in
    nanophotonics opens the way to promising applications, such as widely tunable
    integrated light sources from x-ray to THz frequencies, miniaturized particle
    accelerators, and highly sensitive high-energy particle detectors. Here, we review
    the emerging field of free-electron radiation in nanophotonics. We first present
    a general, unified framework to describe free-electron light–matter interaction
    in arbitrary nanophotonic systems. We then show how this framework sheds light
    on the physical underpinnings of many methods in the field used to control and
    enhance free-electron radiation. Namely, the framework points to the central role
    played by the photonic eigenmodes in controlling the output properties of free-electron
    radiation (e.g., frequency, directionality, and polarization). We then review
    experimental techniques to characterize free-electron radiation in scanning and
    transmission electron microscopes, which have emerged as the central platforms
    for experimental realization of the phenomena described in this review. We further
    discuss various experimental methods to control and extract spectral, angular,
    and polarization-resolved information on free-electron radiation. We conclude
    this review by outlining novel directions for this field, including ultrafast
    and quantum effects in free-electron radiation, tunable short-wavelength emitters
    in the ultraviolet and soft x-ray regimes, and free-electron radiation from topological
    states in photonic crystals.@eng'
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Charles
      foaf_name: Roques-Carmes, Charles
      foaf_surname: Roques-Carmes
      foaf_workInfoHomepage: http://www.librecat.org/personId=e2e68fc9-6505-11ef-a541-eb4e72cc3e82
  - foaf_Person:
      foaf_givenName: Steven E.
      foaf_name: Kooi, Steven E.
      foaf_surname: Kooi
  - foaf_Person:
      foaf_givenName: Yi
      foaf_name: Yang, Yi
      foaf_surname: Yang
  - foaf_Person:
      foaf_givenName: Nicholas
      foaf_name: Rivera, Nicholas
      foaf_surname: Rivera
  - foaf_Person:
      foaf_givenName: Phillip D.
      foaf_name: Keathley, Phillip D.
      foaf_surname: Keathley
  - foaf_Person:
      foaf_givenName: John D.
      foaf_name: Joannopoulos, John D.
      foaf_surname: Joannopoulos
  - foaf_Person:
      foaf_givenName: Steven G.
      foaf_name: Johnson, Steven G.
      foaf_surname: Johnson
  - foaf_Person:
      foaf_givenName: Ido
      foaf_name: Kaminer, Ido
      foaf_surname: Kaminer
  - foaf_Person:
      foaf_givenName: Karl K.
      foaf_name: Berggren, Karl K.
      foaf_surname: Berggren
  - foaf_Person:
      foaf_givenName: Marin
      foaf_name: Soljačić, Marin
      foaf_surname: Soljačić
  bibo_doi: 10.1063/5.0118096
  bibo_issue: '1'
  bibo_volume: 10
  dct_date: 2023^xs_gYear
  dct_isPartOf:
  - http://id.crossref.org/issn/1931-9401
  dct_language: eng
  dct_publisher: AIP Publishing@
  dct_title: Free-electron–light interactions in nanophotonics@
...