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.
Bibliographical noteFunding Information:
This work was supported by the Center for Advanced Meta-Materials (CAMM) funded by the Ministry of Science, ICT, and Future Planning as a Global Frontier Project (CAMM-2014M3A6B3063712) and by the National Research Foundation of Korea(NRF) Grant funded by the Korea government (MSIP) (No. 2015001948).
© 2018 American Physical Society.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)