Microwave seminar | 27 November 2025

The term “Cherenkov-diffraction radiation” (ChDR) has emerged over the past two decades, it refers to the type of Cherenkov radiation generated on a dielectric radiator (target) by charged particle bunches moving, as a rule, along one of its surfaces (or along the corresponding vacuum channel in the target) and interacting with it through the Coulomb field. Interest in this topic is due to developing modern non-invasive methods of electron bunch diagnostics, as well as the prospects of beam-driven methods of generating narrowband radiation (primarily in the THz and sub-THz ranges) [1-4].

First, this report devoted to the description of the “band-pass filter” effect which consists in appearance of a sufficiently narrow resonant peak of ChDR intensity at the wavelengths which are much less than the impact-parameter (the impact-parameter is, for example, the radius of the corresponding vacuum channel in the axisymmetric radiator) [5]. This effect can be observed in the case when the target surface interacting with the bunch is “modified” by the grid composed of thin wires and characterized by the relatively small cell size (i.e. metasurface).

Second, the report presents results of investigation of electromagnetic radiation of a thin charged particle bunch passing through two parallel metasurfaces comprised by thin wire grids with square cells (galvanic contact in the cross points is assumed); the distance between grids is supposed to be much larger than the cell size.

Main paper/arXiv, related to the seminar, and other references

[1] Sei N., Takahashi T. First demonstration of coherent Cherenkov radiation matched to circular plane wave // Sci. Rep. 2017. V. 7. P. 17440.
[2] Tao Z., Sun L., Zhou Z., Xu H., Liu W. High-Power Single-Cycle Terahertz Cherenkov Radiation Using a High-Charge Bunch to Drive Dielectric Prisms // IEEE Trans. Plasma Sci. 2023. V. 51. No. 7. P. 2098.
[3] Karataev P. et al. Ultra-Monochromatic Far-Infrared Cherenkov Diffraction Radiation in a Super-Radiant Regime // Scientific Reports. 2020. V. 10(1). P. 20961.
[4] Kieffer R. et al. Direct Observation of Incoherent Cherenkov Diffraction Radiation in the Visible Range // Phys. Rev. Lett. 2018. V. 121. P. 054802.
[5] Галямин С.Н., Климов И.А., Григорьев С.Г., Тюхтин А.В. Полосовой фильтр для излучения Вавилова-Черенкова // ЖТФ. Принято к печати.