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| Main Authors: | , |
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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2405.02284 |
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| _version_ | 1866913594962083840 |
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| author | Saari, Peeter Besieris, Ioannis |
| author_facet | Saari, Peeter Besieris, Ioannis |
| contents | 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+1)-dimensional unidirectional monochromatic wave and in a (2+1)D spatio-temporal wave packet, 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 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). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2405_02284 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Study of energy backflow in unidirectional monochromatic and space-time waves Saari, Peeter Besieris, Ioannis Optics 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+1)-dimensional unidirectional monochromatic wave and in a (2+1)D spatio-temporal wave packet, 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 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). |
| title | Study of energy backflow in unidirectional monochromatic and space-time waves |
| topic | Optics |
| url | https://arxiv.org/abs/2405.02284 |