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 |
|---|---|
| Article number | 063802 |
| Number of pages | 9 |
| Journal | Physical Review A |
| Volume | 100 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2 Dec 2019 |
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics