In this work, we present efficient coding metasurfaces for acoustic-wave field manipulations. Distinct from the conventional metasurfaces usually having a complex configuration along the surface, our proposed metasurfaces are compact and composed of bipartite units: hornlike helical structures and air. Two kinds of hornlike helical units, defined as logical units “1” and “1/2,” are employed to provide phase differences of $\pi$ and $\pi /2$ compared to air (logical unit “0”). To demonstrate such a simple yet efficient design possessing various fascinating functionalities, we first realize acoustic splitting with suppressed side lobes by suitably arranging logical units 1 and 0. Then, acoustic bending is further achieved with logical units 1/2 and 0. Experiments are conducted to validate these acoustic field manipulations with a broadband characteristic, whose results are consistent with the analytical predictions and simulations. Because of the advantages of the broadband feature and compact size, our proposed coding metasurfaces could contribute to designing devices for manipulating acoustic propagation in desired manners.

• Received 10 January 2019
• Revised 5 April 2019

DOI:https://doi.org/10.1103/PhysRevApplied.11.064033