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Metadiffusers: Deep-subwavelength sound diffusers

We present deep-subwavelength diffusing surfaces based on acoustic metamaterials, namely metadiffusers. These sound diffusers are rigidly backed slotted panels, with each slit being loaded by an array of Helmholtz resonators. Strong dispersion is produced in the slits and slow sound conditions are i...

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Autores principales: Jiménez, Noé, Cox, Trevor J., Romero-García, Vicent, Groby, Jean-Philippe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5511165/
https://www.ncbi.nlm.nih.gov/pubmed/28710374
http://dx.doi.org/10.1038/s41598-017-05710-5
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author Jiménez, Noé
Cox, Trevor J.
Romero-García, Vicent
Groby, Jean-Philippe
author_facet Jiménez, Noé
Cox, Trevor J.
Romero-García, Vicent
Groby, Jean-Philippe
author_sort Jiménez, Noé
collection PubMed
description We present deep-subwavelength diffusing surfaces based on acoustic metamaterials, namely metadiffusers. These sound diffusers are rigidly backed slotted panels, with each slit being loaded by an array of Helmholtz resonators. Strong dispersion is produced in the slits and slow sound conditions are induced. Thus, the effective thickness of the panel is lengthened introducing its quarter wavelength resonance in the deep-subwavelength regime. By tuning the geometry of the metamaterial, the reflection coefficient of the panel can be tailored to obtain either a custom reflection phase, moderate or even perfect absorption. Using these concepts, we present ultra-thin diffusers where the geometry of the metadiffuser has been tuned to obtain surfaces with spatially dependent reflection coefficients having uniform magnitude Fourier transforms. Various designs are presented where, quadratic residue, primitive root and ternary sequence diffusers are mimicked by metadiffusers whose thickness are 1/46 to 1/20 times the design wavelength, i.e., between about a twentieth and a tenth of the thickness of traditional designs. Finally, a broadband metadiffuser panel of 3 cm thick was designed using optimization methods for frequencies ranging from 250 Hz to 2 kHz.
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spelling pubmed-55111652017-07-17 Metadiffusers: Deep-subwavelength sound diffusers Jiménez, Noé Cox, Trevor J. Romero-García, Vicent Groby, Jean-Philippe Sci Rep Article We present deep-subwavelength diffusing surfaces based on acoustic metamaterials, namely metadiffusers. These sound diffusers are rigidly backed slotted panels, with each slit being loaded by an array of Helmholtz resonators. Strong dispersion is produced in the slits and slow sound conditions are induced. Thus, the effective thickness of the panel is lengthened introducing its quarter wavelength resonance in the deep-subwavelength regime. By tuning the geometry of the metamaterial, the reflection coefficient of the panel can be tailored to obtain either a custom reflection phase, moderate or even perfect absorption. Using these concepts, we present ultra-thin diffusers where the geometry of the metadiffuser has been tuned to obtain surfaces with spatially dependent reflection coefficients having uniform magnitude Fourier transforms. Various designs are presented where, quadratic residue, primitive root and ternary sequence diffusers are mimicked by metadiffusers whose thickness are 1/46 to 1/20 times the design wavelength, i.e., between about a twentieth and a tenth of the thickness of traditional designs. Finally, a broadband metadiffuser panel of 3 cm thick was designed using optimization methods for frequencies ranging from 250 Hz to 2 kHz. Nature Publishing Group UK 2017-07-14 /pmc/articles/PMC5511165/ /pubmed/28710374 http://dx.doi.org/10.1038/s41598-017-05710-5 Text en © The Author(s) 2017 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
Jiménez, Noé
Cox, Trevor J.
Romero-García, Vicent
Groby, Jean-Philippe
Metadiffusers: Deep-subwavelength sound diffusers
title Metadiffusers: Deep-subwavelength sound diffusers
title_full Metadiffusers: Deep-subwavelength sound diffusers
title_fullStr Metadiffusers: Deep-subwavelength sound diffusers
title_full_unstemmed Metadiffusers: Deep-subwavelength sound diffusers
title_short Metadiffusers: Deep-subwavelength sound diffusers
title_sort metadiffusers: deep-subwavelength sound diffusers
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5511165/
https://www.ncbi.nlm.nih.gov/pubmed/28710374
http://dx.doi.org/10.1038/s41598-017-05710-5
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