Monochromatic Cherenkov diffraction radiation from continuous coupling of an electron beam to a thin dielectric slab...

A scheme for the generation of monochromatic Cherenkov radiation in a thin dielectric layer is proposed. The electrons travel in a vacuum parallel to a dielectric, exciting a single synchronous electromagnetic waveguide mode. This way of obtaining monochromatic light coupled to free electrons may constitute a new, to the best of our knowledge, platform for quantum optics experiments with free electrons. The proposed scheme is studied quantitatively (radiation power and radiation efficiency) for near-infrared radiation in silicon induced by a 100 keV electron beam, using time-domain and frequency-domain numerical simulations, with material absorption and dispersion taken into account. This method of radiation generation can be scaled from ultraviolet to terahertz radiation by changing the thickness of the dielectric layer and choosing a material with low loss at the desired wavelength. A comparison with conventional Cherenkov radiation and Cherenkov diffraction radiation is also presented.