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

作者：Paul H. Otsuka, Sylvain Mézil, Osamu Matsuda, Motonobu Tomoda, A. A. Maznev, Tian Gan, Nicholas X. Fang, Nicholas Boechler, Vitalyi Gusev, Oliver B. Wright · 发表于：New Journal of Physics · 年份：2018 · DOI：10.1088/1367-2630/aa9298 · 被引用次数：39 · 研究领域：Acoustic Wave Phenomena Research、Underwater Acoustics Research、Speech and Audio Processing

We extend time-domain imaging in acoustic metamaterials to gigahertz frequencies. Using a sample consisting of a regular array of ∼1 μ m 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.