Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses
Abstract Subwavelength imaging of elastic/acoustic waves using phononic crystals (PCs) is limited to a narrow frequency range via the two existing mechanisms that utilize either the intense Bragg scattering in the first phonon band or negative effective properties (left-handed material) in the secon...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2023-05-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-023-34314-5 |
| _version_ | 1797832179464536064 |
|---|---|
| author | Hrishikesh Danawe Serife Tol |
| author_facet | Hrishikesh Danawe Serife Tol |
| author_sort | Hrishikesh Danawe |
| collection | DOAJ |
| description | Abstract Subwavelength imaging of elastic/acoustic waves using phononic crystals (PCs) is limited to a narrow frequency range via the two existing mechanisms that utilize either the intense Bragg scattering in the first phonon band or negative effective properties (left-handed material) in the second (or higher) phonon band. In the first phonon band, the imaging phenomenon can only exist at frequencies closer to the first Bragg band gap where the equal frequency contours (EFCs) are convex. Whereas, for the left-handed materials, the subwavelength imaging is restricted to a narrow frequency region where wave vectors in PC and background material are close to each other, which is essential for single-point image formation. In this work, we propose a PC lens for broadband subwavelength imaging of flexural waves in plates exploiting the second phonon band and the anisotropy of a PC lattice for the first time. Using a square lattice design with square-shaped EFCs, we enable the group velocity vector to always be perpendicular to the lens interface irrespective of the frequency and incidence angle; thus, resulting in a broadband imaging capability. We numerically and experimentally demonstrate subwavelength imaging using this concept over a significantly broadband frequency range. |
| first_indexed | 2024-04-09T14:03:38Z |
| format | Article |
| id | doaj.art-b94ce565c50043a280c51bf08720395c |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-09T14:03:38Z |
| publishDate | 2023-05-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-b94ce565c50043a280c51bf08720395c2023-05-07T11:10:12ZengNature PortfolioScientific Reports2045-23222023-05-011311810.1038/s41598-023-34314-5Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lensesHrishikesh Danawe0Serife Tol1Department of Mechanical Engineering, University of MichiganDepartment of Mechanical Engineering, University of MichiganAbstract Subwavelength imaging of elastic/acoustic waves using phononic crystals (PCs) is limited to a narrow frequency range via the two existing mechanisms that utilize either the intense Bragg scattering in the first phonon band or negative effective properties (left-handed material) in the second (or higher) phonon band. In the first phonon band, the imaging phenomenon can only exist at frequencies closer to the first Bragg band gap where the equal frequency contours (EFCs) are convex. Whereas, for the left-handed materials, the subwavelength imaging is restricted to a narrow frequency region where wave vectors in PC and background material are close to each other, which is essential for single-point image formation. In this work, we propose a PC lens for broadband subwavelength imaging of flexural waves in plates exploiting the second phonon band and the anisotropy of a PC lattice for the first time. Using a square lattice design with square-shaped EFCs, we enable the group velocity vector to always be perpendicular to the lens interface irrespective of the frequency and incidence angle; thus, resulting in a broadband imaging capability. We numerically and experimentally demonstrate subwavelength imaging using this concept over a significantly broadband frequency range.https://doi.org/10.1038/s41598-023-34314-5 |
| spellingShingle | Hrishikesh Danawe Serife Tol Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses Scientific Reports |
| title | Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| title_full | Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| title_fullStr | Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| title_full_unstemmed | Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| title_short | Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| title_sort | broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses |
| url | https://doi.org/10.1038/s41598-023-34314-5 |
| work_keys_str_mv | AT hrishikeshdanawe broadbandsubwavelengthimagingofflexuralelasticwavesinflatphononiccrystallenses AT serifetol broadbandsubwavelengthimagingofflexuralelasticwavesinflatphononiccrystallenses |