Ultrathin Resistive Sheets for Broadband Coherent Absorption and Symmetrization of Acoustic Waves

The manipulation of acoustic waves is experimentally and theoretically investigated based on the concept of coherent perfect absorption. It is shown that the absolute control of antisymmetric modes of an acoustic duct is possible using an ultrathin wire mesh. By varying the relative phase of two counterpropagating (normal or oblique) incident waves, the absorption due to wire mesh can be tuned from zero to unity. Experimental as well as numerical results demonstrate that this phenomenon is extremely broadband???allowing, for instance, the symmetrization of the acoustic wave with a short pulse in the time domain.