Broadband diffusion of acoustic waves via a 1-bit coding metasurface

The acoustic diffusers play key roles in noise control and ultrasound imaging. Here, we propose a new approach to design broadband acoustic diffusers with 1-bit acoustic coding metasurfaces, which are composed of two basic unit cells with out-of-phase responses. We show that the 1-bit acoustic coding metasurfaces are able to diffuse the acoustic waves at will by optimizing the coding sequences, giving rise to ultralow backscattering as desired.