Near-field wave interactions with defects and their implications on sub-wavelength acoustic imaging

Acoustic metamaterial concepts, such as metalenses and hyperlenses, have been studied with much interest for super-resolution imaging. However, the physics of wave scattering by sub-wavelength sized defects is still not very well understood. Here, we present studies on acoustic wave interactions wit...

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Bibliographic Details
Published in:Journal of applied physics 2024-02, Vol.135 (8)
Main Authors: Zul Karnain, Ahmed Al, Syed Akbar Ali, Mohamed Subair, Chelat, Sreehari Kollancheri, Lopato, Przemyslaw, Rajagopal, Prabhu
Format: Article
Language:English
Subjects:
Acoustic imaging
Acoustic waves
Defects
Far fields
Image resolution
Metamaterials
Wave interaction
Wave scattering
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Summary:Acoustic metamaterial concepts, such as metalenses and hyperlenses, have been studied with much interest for super-resolution imaging. However, the physics of wave scattering by sub-wavelength sized defects is still not very well understood. Here, we present studies on acoustic wave interactions with circular defects of sizes varying from over a wavelength to sub-wavelength scale. Near- and far-field scattering patterns of single circular defects are presented, connecting them to analytical frameworks. Scattering field signatures produced by two identical circular defects of different sizes placed side by side are then discussed. The separation distance between the defects is among the parameters varied to understand the effects of geometric features in successful imaging. Experimental results are presented to support the predictions reported in the paper. The insights have important implications for sub-wavelength imaging using acoustic metamaterials.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0185413