Energy Backflow in Unidirectional Monochromatic and Space–Time Waves
| dc.contributor.author | Saari, Peeter | en |
| dc.contributor.author | Besieris, Ioannis M. | en |
| dc.date.accessioned | 2025-01-08T14:11:45Z | en |
| dc.date.available | 2025-01-08T14:11:45Z | en |
| dc.date.issued | 2024-11-29 | en |
| dc.date.updated | 2024-12-27T14:02:09Z | en |
| dc.description.abstract | Backflow, or retropropagation, is a counterintuitive phenomenon whereby for a forward-propagating wave the energy locally propagates backward. In the context of backflow, physically most interesting are the so-called unidirectional waves, which contain only forward-propagating plane wave constituents. Yet, very few such waves possessing closed-form analytic expressions for evaluation of the Poynting vector are known. In this study, we examine energy backflow in a novel (2+time)-dimensional unidirectional monochromatic wave and in a (2+1)D spatiotemporal wavepacket, analytic expressions which we succeeded to find. We also present a detailed study of the backflow in the “needle” pulse. This is an interesting model object because well-known superluminal non-diffracting space–time wave packets can be derived from its simple factored wave function. Finally, we study the backflow in an unidirectional version of the so-called focus wave mode—a pulse propagating luminally and without spread, which is the first and most studied representative of the (3+1)D non-diffracting space–time wave packets (also referred to as spatiotemporally localized waves). | en |
| dc.description.version | Published version | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.citation | Saari, P.; Besieris, I.M. Energy Backflow in Unidirectional Monochromatic and Space–Time Waves. Photonics 2024, 11, 1129. | en |
| dc.identifier.doi | https://doi.org/10.3390/photonics11121129 | en |
| dc.identifier.uri | https://hdl.handle.net/10919/123956 | en |
| dc.language.iso | en | en |
| dc.publisher | MDPI | en |
| dc.rights | Creative Commons Attribution 4.0 International | en |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | en |
| dc.title | Energy Backflow in Unidirectional Monochromatic and Space–Time Waves | en |
| dc.title.serial | Photonics | en |
| dc.type | Article - Refereed | en |
| dc.type.dcmitype | Text | en |