Bound states in the continuum in circular clusters of scatterers

In this work we study the localization of flexural waves in highly symmetric clusters of scatterers. It is shown that when the scatterers are placed regularly in the perimeter of a circumference, the quality factor of the resonances strongly increases with the number of scatterers in the cluster. It...

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Main Authors: Marc Martí-Sabaté, Bahram Djafari-Rouhani, Dani Torrent
Format: Article
Language:English
Published: American Physical Society 2023-02-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.5.013131
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author Marc Martí-Sabaté
Bahram Djafari-Rouhani
Dani Torrent
author_facet Marc Martí-Sabaté
Bahram Djafari-Rouhani
Dani Torrent
author_sort Marc Martí-Sabaté
collection DOAJ
description In this work we study the localization of flexural waves in highly symmetric clusters of scatterers. It is shown that when the scatterers are placed regularly in the perimeter of a circumference, the quality factor of the resonances strongly increases with the number of scatterers in the cluster. It is also found that in the continuous limit, that is to say, when the number of scatterers tends to infinite, the quality factor is infinite so that the modes belong to the class of the so-called bound states in the continuum or BICs, and an analytical expression for the resonant frequency is found. These modes have different multipolar symmetries, and we show that for high multipolar orders the modes tend to localize at the border of the circumference, therefore forming a whispering gallery mode with an extraordinarily high quality factor. Numerical experiments are performed to check the robustness of these modes under different types of disorder and also to study their excitation from the far field. Although we have focused our study on flexural waves, the methodology presented in this work can be applied to other classical waves, like electromagnetic or acoustic waves, being a promising approach for the design of high-quality resonators based on finite clusters of scatterers.
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spelling doaj.art-34b9fda19f9443cb8c7c0fd40c3474982024-04-12T17:28:44ZengAmerican Physical SocietyPhysical Review Research2643-15642023-02-015101313110.1103/PhysRevResearch.5.013131Bound states in the continuum in circular clusters of scatterersMarc Martí-SabatéBahram Djafari-RouhaniDani TorrentIn this work we study the localization of flexural waves in highly symmetric clusters of scatterers. It is shown that when the scatterers are placed regularly in the perimeter of a circumference, the quality factor of the resonances strongly increases with the number of scatterers in the cluster. It is also found that in the continuous limit, that is to say, when the number of scatterers tends to infinite, the quality factor is infinite so that the modes belong to the class of the so-called bound states in the continuum or BICs, and an analytical expression for the resonant frequency is found. These modes have different multipolar symmetries, and we show that for high multipolar orders the modes tend to localize at the border of the circumference, therefore forming a whispering gallery mode with an extraordinarily high quality factor. Numerical experiments are performed to check the robustness of these modes under different types of disorder and also to study their excitation from the far field. Although we have focused our study on flexural waves, the methodology presented in this work can be applied to other classical waves, like electromagnetic or acoustic waves, being a promising approach for the design of high-quality resonators based on finite clusters of scatterers.http://doi.org/10.1103/PhysRevResearch.5.013131
spellingShingle Marc Martí-Sabaté
Bahram Djafari-Rouhani
Dani Torrent
Bound states in the continuum in circular clusters of scatterers
Physical Review Research
title Bound states in the continuum in circular clusters of scatterers
title_full Bound states in the continuum in circular clusters of scatterers
title_fullStr Bound states in the continuum in circular clusters of scatterers
title_full_unstemmed Bound states in the continuum in circular clusters of scatterers
title_short Bound states in the continuum in circular clusters of scatterers
title_sort bound states in the continuum in circular clusters of scatterers
url http://doi.org/10.1103/PhysRevResearch.5.013131
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