Abstract
Electrically charged particles, moving faster than the speed of light in a medium, emit Cherenkov radiation. Theory predicts electric and magnetic dipoles to radiate as well, with a puzzling behavior for magnetic dipoles pointing in transversal direction [I. M. Frank, Izv. Akad. Nauk SSSR, Ser. Fiz. 6, 3 (1942)]. A discontinuous Cherenkov spectrum should appear at threshold, where the particle velocity matches the phase velocity of light. Here we deduce theoretically that light bullets [Y. Silberberg, Opt. Lett. 15, 1282 (1990)OPLEDP0146-959210.1364/OL.15.001282] emit an analogous radiation with exactly the same spectral discontinuity for point-like sources. For extended sources the discontinuity turns into a spectral peak at threshold. We argue that this Cherenkov radiation has been experimentally observed in the first attempt to measure Hawking radiation in optics [F. Belgiorno, Phys. Rev. Lett. 105, 203901 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.203901] thus giving experimental evidence for a puzzle in Cherenkov radiation instead.
Original language | English |
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Article number | 063802 |
Number of pages | 9 |
Journal | Physical Review A |
Volume | 100 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2 Dec 2019 |
Funding
This paper is dedicated to the memory of Yaron Silberberg. We are most grateful to him and to David Bermudez, Yehonathan Drori, and Itay Griniasty for scientific discussions related to this paper. Our work was supported by the European Research Council, the Israel Science Foundation, and the Murray B. Koffler Professorial Chair. U.L. and Y.R. contributed equally to this work.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics