Tunable sound transmission through water–air interface by membrane-sealed bubble metasurface.

The acoustic impedance mismatch between water and air limits the acoustic communication through the water–air interface. Here, based on the resonances of bubbles, we propose a metasurface consisting of bubbles sealed with membranes for perfect sound transmission at the water–air interface. We have experimentally achieved sound transmission enhancement of over 20 dB at 380–510 Hz, with the thickness of the metasurface about 1/180 times air wavelength. By flexibly adjusting the immersion depth, the metasurface is able to operate at multiple frequencies. The effects of viscosity and geometry of bubbles are discussed simulatively. The present work is relevant to the practical design of advanced acoustic devices for transmedia communication. [ABSTRACT FROM AUTHOR]