Reflected wavefront manipulation by acoustic metasurface with anisotropic local resonant units

Abstract: Metasurfaces with planar profile and wave front shaping capabilities would be ideally suitable to improve the performance of acoustic wave-based applications. It is significant that the general Snell's law provides a new approach to engineer the phase profile of reflected acoustic wave. Here, we present a new type of acoustic metasurface based on three-component composites which contain a steel ball coated with a thin elliptical layer of silicone rubber and embedded in epoxy. The acoustic metasurface with changeable radii of steel balls can realize the anomalous reflections, a planar acoustic lens through designed gradient phase profile. The acoustic metasurface contained with elaborately selected three-component composites, as a skin cloak, successfully achieve the acoustical invisibility.