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The generation of Cherenkov radiation when a charged particle passes through a cylindrical channel in a dielectric is a “key” problem for several promising areas in modern electrodynamics, e.g., development of novel techniques for non-invasive bunch diagnostics [1-2] and new radiation sources [3-5]. The solution of this problem is well-known [6]: when the channel is sufficiently narrow, the radiation is produced “almost” as if it were in an infinite dielectric, and the impact of the channel may be compared to a low-pass filter since high frequencies or short wavelengths (on the order of or smaller than the channel dimension) are significantly attenuated in the radiation spectrum.
In this paper, we investigate the impact of a small-period grid of thin parallel wires located in a channel close to the surface of a dielectric on radiation characteristics. The grid under discussion is a simple example of a “non-local” metasurface, since the tangential derivative of the average surface current is present in the averaged boundary conditions (ABC) [7-8]. “Non-local” surfaces have been the focus of research in recent years due to their potential for controlling electromagnetic radiation [9-10]. However, boundary value problems involving ABC in cases where the grid is near the dielectric (in this case, ABC undergo significant modification [11]) and the source is a moving charged particle, have not yet been analyzed. The primary physical outcome of this research is the identification and characterization of a novel physical phenomenon named the “bandpass filtering effect” for Cherenkov radiation.
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[2] P. Karataev et al. Sci. Rep. 10, 20961 (2020).
[3] N. Sei and T. Takahashi, Sci. Rep. 7, 17440 (2017).
[4] A.V. Tyukhtin et al., Phys. Rev. A 99, 023810 (2019).
[5] A.V. Tyukhtin et al., Phys. Rev. A 102, 053514 (2020).
[6] B.M. Bolotovskii, Sov. Phys. Usp. 4 (1962) 781.
[7] M.I. Kontorovich, M.I. Astrakhan, V.P. Akimov, G.A. Fersman. Electrodynamics of grid structures. Moscow, Radio I Svyaz, 1987 (in Russian).
[8] S.B. Glybovski et al., IEEE Trans. AP 62, 3348 (2014).
[9] O. Luukkonen et al., IEEE Trans. MTT 57, 2692 (2009).
[10] D. Vabichevich et al., IEEE Ant. Wireless Propag. Lett. 22, 2808 (2023).
[11] V.P. Akimov. Electrodynamics of grid structures. D. Sc. thesis. SPbSTU, 1998.
