1-bit absorption-diffusion acoustic coding metasurface

Acoustic metasurfaces demonstrate unprecedented potential for flexible capabilities of the acoustic wavefront manipulation. Especially, acoustic diffusers and absorbers via acoustic metasurfaces have garnered significant attention of researchers due to the excellent performance. However, although these diffusers and absorbers have achieved excellent acoustic scattering suppression, it still remains a significant challenge to obtain higher scattering suppression. Here, a 1-bit absorption-diffusion acoustic coding metasurface (ADM) is proposed, which can achieve high-performance acoustic backward scattering reduction in the operating frequency by combining the advantages of acoustic diffusers and absorbers. In order to realize the proposed ADM, two kinds of subwavelength dual-layer unit cells with opposite reflection phases and low amplitudes are introduced. Both simulated and experimental results demonstrate that the proposed ADM can achieve the pre-designed backward acoustic scattering reduction. The proposed integrated mechanism can provide a new method for designing high-performance acoustic metasurfaces, which can have potential applications in stealth technology, noise control and other relevant applications.