Slow waves on long helices
Abstract 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 metalli...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2022-02-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-05345-1 |
| _version_ | 1828135801479757824 |
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| author | Lauren E. Barr Gareth P. Ward Alastair P. Hibbins Euan Hendry J. Roy Sambles |
| author_facet | Lauren E. Barr Gareth P. Ward Alastair P. Hibbins Euan Hendry J. Roy Sambles |
| author_sort | Lauren E. Barr |
| collection | DOAJ |
| description | Abstract 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 $$\sim$$ ∼ 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. |
| first_indexed | 2024-04-11T17:53:02Z |
| format | Article |
| id | doaj.art-3ec9cba8688944b0ab6bc30013f11d74 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-11T17:53:02Z |
| publishDate | 2022-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-3ec9cba8688944b0ab6bc30013f11d742022-12-22T04:10:59ZengNature PortfolioScientific Reports2045-23222022-02-011211910.1038/s41598-022-05345-1Slow waves on long helicesLauren E. Barr0Gareth P. Ward1Alastair P. Hibbins2Euan Hendry3J. Roy Sambles4Department of Physics and Astronomy, University of ExeterDepartment of Physics and Astronomy, University of ExeterDepartment of Physics and Astronomy, University of ExeterDepartment of Physics and Astronomy, University of ExeterDepartment of Physics and Astronomy, University of ExeterAbstract 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 $$\sim$$ ∼ 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.https://doi.org/10.1038/s41598-022-05345-1 |
| spellingShingle | Lauren E. Barr Gareth P. Ward Alastair P. Hibbins Euan Hendry J. Roy Sambles Slow waves on long helices Scientific Reports |
| 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 |
| url | https://doi.org/10.1038/s41598-022-05345-1 |
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