Publications [#336182] of Steven A. Cummer

Papers Published

1. Shen, C; Cummer, SA, Harnessing Multiple Internal Reflections to Design Highly Absorptive Acoustic Metasurfaces, Physical Review Applied, vol. 9 no. 5 (May, 2018), American Physical Society (APS) [doi]
   (last updated on 2023/06/01)

   Abstract:
   The rapid development of metasurfaces has enabled numerous intriguing applications with acoustically thin sheets. Here we report the theory and experimental realization of a nonresonant sound-absorbing strategy using metasurfaces by harnessing multiple internal reflections. We theoretically and numerically show that the higher-order diffraction of thin gradient-index metasurfaces is tied to multiple internal reflections inside the unit cells. Highly absorbing acoustic metasurfaces can be realized by enforcing multiple internal reflections together with a small amount of loss. A reflective gradient-index acoustic metasurface is designed based on the theory, and we further experimentally verify the performance using a three-dimensional printed prototype. Measurements show over 99% energy absorption at the peak frequency and a 95% energy absorption bandwidth of around 600 Hz. The proposed mechanism provides an alternative route for sound absorption without the necessity of high absorption of the individual unit cells.