Ultrasparse Acoustic Absorbers Enabling Fluid Flow and Visible-Light Controls

Abstract

Although conventional acoustic absorbers work well for noise suppression, they also block fluid (air) flow and visible light, which is inconvenient if $e.g.$ one wants a quiet house near a busy road. This study uses sparsely arranged acoustic resonators that permit fluid flow yet effectively prevent sound propagation. Furthermore, when such a sparse absorber is combined with optical cloaking technology, it can be transparent to the eye. This approach enables innovative applications of multifunctional acoustic metamaterials.