Time-domain imaging of gigahertz surface waves on an acoustic metamaterial

We extend time-domain imaging in acoustic metamaterials to gigahertz frequencies. Using a sample consisting of a regular array of ~1 μm diameter silica microspheres forming a two-dimensional triangular lattice on a substrate, we implement an ultrafast technique to probe surface acoustic wave propaga...

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Bibliographic Details
Main Authors: Otsuka, Paul H, Mezil, Sylvain, Matsuda, Osamu, Tomoda, Motonobu, Boechler, Nicholas, Gusev, Vitalyi E, Wright, Oliver B, Maznev, Alexei, Gan, Tian, Fang, Xuanlai
Other Authors: Massachusetts Institute of Technology. Department of Chemistry
Format: Article
Published: IOP Publishing 2018
Online Access:http://hdl.handle.net/1721.1/119213
https://orcid.org/0000-0001-5713-629X
Description
Summary:We extend time-domain imaging in acoustic metamaterials to gigahertz frequencies. Using a sample consisting of a regular array of ~1 μm diameter silica microspheres forming a two-dimensional triangular lattice on a substrate, we implement an ultrafast technique to probe surface acoustic wave propagation inside the metamaterial area and incident on the metamaterial from a region containing no microspheres, which reveals the acoustic metamaterial dispersion, the presence of band gaps and the acoustic transmission properties of the interface. A theoretical model of this locally resonant metamaterial based on normal and shear-rotational resonances of the spheres fits the data well. Using this model, we show analytically how the sphere elastic coupling parameters influence the gap widths.