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Nanofocusing of structured light for quadrupolar light-matter interactions

The spatial structure of an electromagnetic field can determine the characteristics of light-matter interactions. A strong gradient of light in the near field can excite dipole-forbidden atomic transitions, e.g., electric quadrupole transitions, which are rarely observed under plane-wave far-field i...

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Detalles Bibliográficos
Autores principales: Sakai, Kyosuke, Yamamoto, Takeaki, Sasaki, Keiji
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5958059/
https://www.ncbi.nlm.nih.gov/pubmed/29773875
http://dx.doi.org/10.1038/s41598-018-26175-0
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author Sakai, Kyosuke
Yamamoto, Takeaki
Sasaki, Keiji
author_facet Sakai, Kyosuke
Yamamoto, Takeaki
Sasaki, Keiji
author_sort Sakai, Kyosuke
collection PubMed
description The spatial structure of an electromagnetic field can determine the characteristics of light-matter interactions. A strong gradient of light in the near field can excite dipole-forbidden atomic transitions, e.g., electric quadrupole transitions, which are rarely observed under plane-wave far-field illumination. Structured light with a higher-order orbital angular momentum state may also modulate the selection rules in which an atom can absorb two quanta of angular momentum: one from the spin and another from the spatial structure of the beam. Here, we numerically demonstrate a strong focusing of structured light with a higher-order orbital angular momentum state in the near field. A quadrupole field was confined within a gap region of several tens of nanometres in a plasmonic tetramer structure. A plasmonic crystal surrounding the tetramer structure provides a robust antenna effect, where the incident structured light can be strongly coupled to the quadrupole field in the gap region with a larger alignment tolerance. The proposed system is expected to provide a platform for light-matter interactions with strong multipolar effects.
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spelling pubmed-59580592018-05-21 Nanofocusing of structured light for quadrupolar light-matter interactions Sakai, Kyosuke Yamamoto, Takeaki Sasaki, Keiji Sci Rep Article The spatial structure of an electromagnetic field can determine the characteristics of light-matter interactions. A strong gradient of light in the near field can excite dipole-forbidden atomic transitions, e.g., electric quadrupole transitions, which are rarely observed under plane-wave far-field illumination. Structured light with a higher-order orbital angular momentum state may also modulate the selection rules in which an atom can absorb two quanta of angular momentum: one from the spin and another from the spatial structure of the beam. Here, we numerically demonstrate a strong focusing of structured light with a higher-order orbital angular momentum state in the near field. A quadrupole field was confined within a gap region of several tens of nanometres in a plasmonic tetramer structure. A plasmonic crystal surrounding the tetramer structure provides a robust antenna effect, where the incident structured light can be strongly coupled to the quadrupole field in the gap region with a larger alignment tolerance. The proposed system is expected to provide a platform for light-matter interactions with strong multipolar effects. Nature Publishing Group UK 2018-05-17 /pmc/articles/PMC5958059/ /pubmed/29773875 http://dx.doi.org/10.1038/s41598-018-26175-0 Text en © The Author(s) 2018 Open Access This 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 license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license 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 license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Sakai, Kyosuke
Yamamoto, Takeaki
Sasaki, Keiji
Nanofocusing of structured light for quadrupolar light-matter interactions
title Nanofocusing of structured light for quadrupolar light-matter interactions
title_full Nanofocusing of structured light for quadrupolar light-matter interactions
title_fullStr Nanofocusing of structured light for quadrupolar light-matter interactions
title_full_unstemmed Nanofocusing of structured light for quadrupolar light-matter interactions
title_short Nanofocusing of structured light for quadrupolar light-matter interactions
title_sort nanofocusing of structured light for quadrupolar light-matter interactions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5958059/
https://www.ncbi.nlm.nih.gov/pubmed/29773875
http://dx.doi.org/10.1038/s41598-018-26175-0
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