Abstract
We propose the use of an ultrathin cloak made of an acoustic surface impedance that leads to invisibility for acoustic waves. Unlike current acoustic cloaks that require volumetric metamaterials and a significant shell thickness, the mantle cloak presented here is based on a patterned acoustic metasurface that produces similar effects in a thinner geometry. We show that by covering a cylindrical obstacle by a specific acoustic surface impedance, the total scattering may be significantly reduced in the near-and the far-field, thus suppressing its overall acoustic signature. Potential applications lie in low-detectability, camouflaging, and non-invasive acoustic probing. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3655141]