Broadband diffuse reflections of sound by metasurface with random phase response

Abstract

We have designed an ultrathin planar structure capable of generating diffuse reflections within a broadband. By introducing randomly distributed gradients along the interface, the proposed structure can scatter the incident acoustic waves into all directions and virtually suppress the scattered lobes that will otherwise be remarkable for a planar surface. A practical implementation by labryinthine-like metamaterial with designed phase shift profile is demontrated. The numerical results show that our designed planar surface could be used to mimic a rugged surface as expected. We envision our designed structure to exhibit potentials in applications such as room acoustics and acoustic stealth.