An array of surface-mounted prismatic resonators in the path of Rayleigh wave propagation generates two distinct types of surface-wave bandgaps: longitudinal and flexural-resonance bandgaps, resulting from the hybridization of the Rayleigh wave with the longitudinal and flexural resonances of the resonators, respectively. Longitudinal-resonance bandgaps are broad with asymmetric transmission drops, whereas flexural-resonance bandgaps are narrow with nearly symmetric transmission drops. In this paper, we illuminate these observations by investigating the resonances and anti-resonances of the resonator. With an understanding of how the Rayleigh wave interacts with different boundary conditions, we investigate the clamping conditions imposed by prismatic resonators due to the resonator’s resonances and anti-resonances and interpret the resulting transmission spectra. We demonstrate that, in the case of a single resonator, only the resonator’s longitudinal and flexural resonances are responsible for suppressing Rayleigh waves. In contrast, for a resonator array, both the resonances and the anti-resonances of the resonators contribute to the formation of the longitudinal-resonance bandgaps, unlike the flexural-resonance bandgaps where only the flexural resonances play a role. We also provide an explanation for the observed asymmetry in the transmission drop within the longitudinal-resonance bandgaps by assessing the clamping conditions imposed by the resonators. Finally, we evaluate the transmission characteristics of resonator arrays at the anti-resonance frequencies by varying a few key geometric parameters of the unit cell. These findings provide the conceptual understanding required to design optimized resonators based on matching anti-resonance frequencies with the incident Rayleigh wave frequency in order to achieve enhanced Rayleigh wave suppression.
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Electromagnetically induced transparency and lattice resonances in metasurfaces composed of silicon nanocylinders
Densely packed metasurfaces composed of cylindrical silicon nano-resonators were found to demonstrate the phenomenon of electromagnetically induced transparency at electric dipolar resonances. It was shown that this phenomenon is not related to overlapping of dipolar resonances or to the Kerker’s effects. The observed transparency appeared to be related to interference between waves scattered by nano-resonators and by additional scattering centers including the electric branch of lattice resonances. Coupled resonance fields were also found to contribute to observed phenomena.
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- Award ID(s):
- 1709991
- NSF-PAR ID:
- 10173209
- Date Published:
- Journal Name:
- 7th Advanced Electromagnetics Symposium, Lisbon, Portugal
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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