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Slow waves on long helices
Slowing light in a non-dispersive and controllable fashion opens the door to many new phenomena in photonics. As such, many schemes have been put forward to decrease the velocity of light, most of which are limited in bandwidth or incur high losses. In this paper we show that a long metallic helix s...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8814024/ https://www.ncbi.nlm.nih.gov/pubmed/35115558 http://dx.doi.org/10.1038/s41598-022-05345-1 |
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author | Barr, Lauren E. Ward, Gareth P. Hibbins, Alastair P. Hendry, Euan Sambles, J. Roy |
author_facet | Barr, Lauren E. Ward, Gareth P. Hibbins, Alastair P. Hendry, Euan Sambles, J. Roy |
author_sort | Barr, Lauren E. |
collection | PubMed |
description | Slowing light in a non-dispersive and controllable fashion opens the door to many new phenomena in photonics. As such, many schemes have been put forward to decrease the velocity of light, most of which are limited in bandwidth or incur high losses. In this paper we show that a long metallic helix supports a low-loss, broadband slow wave with a mode index that can be controlled via geometrical design. For one particular geometry, we characterise the dispersion of the mode, finding a relatively constant mode index of [Formula: see text] 45 between 10 and 30 GHz. We compare our experimental results to both a geometrical model and full numerical simulation to quantify and understand the limitations in bandwidth. We find that the bandwidth of the region of linear dispersion is associated with the degree of hybridisation between the fields of a helical mode that travels around the helical wire and an axial mode that disperses along the light line. Finally, we discuss approaches to broaden the frequency range of near-constant mode index: we find that placing a straight wire along the axis of the helix suppresses the interaction between the axial and high index modes supported by the helix, leading to both an increase in bandwidth and a more linear dispersion. |
format | Online Article Text |
id | pubmed-8814024 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-88140242022-02-07 Slow waves on long helices Barr, Lauren E. Ward, Gareth P. Hibbins, Alastair P. Hendry, Euan Sambles, J. Roy Sci Rep Article Slowing light in a non-dispersive and controllable fashion opens the door to many new phenomena in photonics. As such, many schemes have been put forward to decrease the velocity of light, most of which are limited in bandwidth or incur high losses. In this paper we show that a long metallic helix supports a low-loss, broadband slow wave with a mode index that can be controlled via geometrical design. For one particular geometry, we characterise the dispersion of the mode, finding a relatively constant mode index of [Formula: see text] 45 between 10 and 30 GHz. We compare our experimental results to both a geometrical model and full numerical simulation to quantify and understand the limitations in bandwidth. We find that the bandwidth of the region of linear dispersion is associated with the degree of hybridisation between the fields of a helical mode that travels around the helical wire and an axial mode that disperses along the light line. Finally, we discuss approaches to broaden the frequency range of near-constant mode index: we find that placing a straight wire along the axis of the helix suppresses the interaction between the axial and high index modes supported by the helix, leading to both an increase in bandwidth and a more linear dispersion. Nature Publishing Group UK 2022-02-03 /pmc/articles/PMC8814024/ /pubmed/35115558 http://dx.doi.org/10.1038/s41598-022-05345-1 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Article Barr, Lauren E. Ward, Gareth P. Hibbins, Alastair P. Hendry, Euan Sambles, J. Roy Slow waves on long helices |
title | Slow waves on long helices |
title_full | Slow waves on long helices |
title_fullStr | Slow waves on long helices |
title_full_unstemmed | Slow waves on long helices |
title_short | Slow waves on long helices |
title_sort | slow waves on long helices |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8814024/ https://www.ncbi.nlm.nih.gov/pubmed/35115558 http://dx.doi.org/10.1038/s41598-022-05345-1 |
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