Dear Colleagues,

In the past few years the research area involving the intricate interplay between light and free electrons has developed into an exciting new field: free electron quantum optics. Harnessing the weak interaction between free electrons and light requires either very strong electromagnetic fields or the close vicinity of nanostructures, which has only become possible with recent developments in laser and electron beam technology.

Electron beams now make it possible to generate, probe and control light at length scales far below the diffraction limit, enabling fundamental studies of nanophotonics. Photon-induced near-field electron microscopy has shown great potential for visualizing dynamic phenomena such as plasmonics with very high spatial and temporal resolution. Vice versa, the near fields of optically excited plasmon polaritons in nanostructures offer new ways to manipulate and shape electron beams, ultimately enabling aberration-free electron imaging. Strong laser fields can be employed to coherently manipulate the electron wave function in free space by the ponderomotive force for realizing, for example, matter-free Zernike electron phase plates and coherent electron beam splitters. These and other methods for electron wave manipulation offer the intriguing prospect of interaction-free electron microscopy: the “quantum electron microscope”. Finally, the combination of strong laser fields and very precisely tailored 3D nanostructures opens the way to high-gradient dielectric laser acceleration: a particle accelerator on a chip.

The burgeoning field of free electron quantum optics has already generated many fundamental insights and important applications. The latest developments in this exciting new field will be shared in this special issue. We invite researchers and investigators to contribute their original research or review articles to this special issue.

Prof. Dr. Jom Luiten
Guest Editor

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• free electron quantum optics
• cathodoluminescence imaging spectroscopy
• nanophotonics
• photon-induced near-field electron microscopy
• kapitza-dirac effect
• ponderomotive phase plate
• optical electron beam shaping
• ultrafast electron microscopy
• quantum electron microscopy
• quantum degenerate electron beams
• dielectric laser acceleration
• particle accelerator on-a-chip