Metasurface for Water-to-Air Sound Transmission

Effective transmission of sound from water to air is crucial for the enhancement of the detection sensitivity of underwater sound. However, only 0.1% of the acoustic energy is naturally transmitted at such a boundary. At audio frequencies, quarter-wave plates or multilayered antireflection coatings are too bulky for practical use for such enhancement. Here we present an acoustic metasurface of a thickness of only ∼λ/100, where λ is the wavelength in air, consisting of an array of meta-atoms that each contain a set of membranes and an air-filled cavity. We experimentally demonstrate that such a meta-atom increases the transmission of sound at ∼700 Hz by 2 orders of magnitude, allowing about 30% of the incident acoustic power from water to be transmitted into air. Applications include underwater sonic sensing and communication.Received 24 August 2017DOI:https://doi.org/10.1103/PhysRevLett.120.044302© 2018 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAcoustic metamaterialsAcoustic modelingAcoustic wave phenomenaAcousticsLinear acousticsUnderwater acousticsTechniquesDensity functional theory developmentMathematical physics methodsNumerical approximation & analysisProfessional TopicsPhysics & societyGeneral Physics