Willis Metamaterial on a Structured Beam
Bianisotropy is common in electromagnetism whenever a cross-coupling between electric and magnetic responses exists. However, the analogous concept for elastic waves in solids, termed as Willis coupling, is more challenging to observe. It requires coupling between stress and velocity or momentum and...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2019-02-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.9.011040 |
| _version_ | 1818989892562059264 |
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| author | Yongquan Liu Zixian Liang Jian Zhu Lingbo Xia Olivier Mondain-Monval Thomas Brunet Andrea Alù Jensen Li |
| author_facet | Yongquan Liu Zixian Liang Jian Zhu Lingbo Xia Olivier Mondain-Monval Thomas Brunet Andrea Alù Jensen Li |
| author_sort | Yongquan Liu |
| collection | DOAJ |
| description | Bianisotropy is common in electromagnetism whenever a cross-coupling between electric and magnetic responses exists. However, the analogous concept for elastic waves in solids, termed as Willis coupling, is more challenging to observe. It requires coupling between stress and velocity or momentum and strain fields, which is difficult to induce in non-negligible levels, even when using metamaterial structures. Here, we report the experimental realization of a Willis metamaterial for flexural waves. Based on a cantilever bending resonance, we demonstrate asymmetric reflection amplitudes and phases due to Willis coupling. We also show that, by introducing loss in the metamaterial, the asymmetric amplitudes can be controlled and can be used to approach an exceptional point of the non-Hermitian system, at which unidirectional zero reflection occurs. The present work extends conventional propagation theory in plates and beams to include Willis coupling and provides new avenues to tailor flexural waves using artificial structures. |
| first_indexed | 2024-12-20T19:45:42Z |
| format | Article |
| id | doaj.art-294fc2880f0c4fa3b066319ee9c5a3ed |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-20T19:45:42Z |
| publishDate | 2019-02-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-294fc2880f0c4fa3b066319ee9c5a3ed2022-12-21T19:28:25ZengAmerican Physical SocietyPhysical Review X2160-33082019-02-019101104010.1103/PhysRevX.9.011040Willis Metamaterial on a Structured BeamYongquan LiuZixian LiangJian ZhuLingbo XiaOlivier Mondain-MonvalThomas BrunetAndrea AlùJensen LiBianisotropy is common in electromagnetism whenever a cross-coupling between electric and magnetic responses exists. However, the analogous concept for elastic waves in solids, termed as Willis coupling, is more challenging to observe. It requires coupling between stress and velocity or momentum and strain fields, which is difficult to induce in non-negligible levels, even when using metamaterial structures. Here, we report the experimental realization of a Willis metamaterial for flexural waves. Based on a cantilever bending resonance, we demonstrate asymmetric reflection amplitudes and phases due to Willis coupling. We also show that, by introducing loss in the metamaterial, the asymmetric amplitudes can be controlled and can be used to approach an exceptional point of the non-Hermitian system, at which unidirectional zero reflection occurs. The present work extends conventional propagation theory in plates and beams to include Willis coupling and provides new avenues to tailor flexural waves using artificial structures.http://doi.org/10.1103/PhysRevX.9.011040 |
| spellingShingle | Yongquan Liu Zixian Liang Jian Zhu Lingbo Xia Olivier Mondain-Monval Thomas Brunet Andrea Alù Jensen Li Willis Metamaterial on a Structured Beam Physical Review X |
| title | Willis Metamaterial on a Structured Beam |
| title_full | Willis Metamaterial on a Structured Beam |
| title_fullStr | Willis Metamaterial on a Structured Beam |
| title_full_unstemmed | Willis Metamaterial on a Structured Beam |
| title_short | Willis Metamaterial on a Structured Beam |
| title_sort | willis metamaterial on a structured beam |
| url | http://doi.org/10.1103/PhysRevX.9.011040 |
| work_keys_str_mv | AT yongquanliu willismetamaterialonastructuredbeam AT zixianliang willismetamaterialonastructuredbeam AT jianzhu willismetamaterialonastructuredbeam AT lingboxia willismetamaterialonastructuredbeam AT oliviermondainmonval willismetamaterialonastructuredbeam AT thomasbrunet willismetamaterialonastructuredbeam AT andreaalu willismetamaterialonastructuredbeam AT jensenli willismetamaterialonastructuredbeam |