Realization of Dissipation-Enhanced Topological Valley Transport in Phononic Crystal

Dissipation, originating from intrinsic material absorption or leakage to the environment, is usually considered detrimental to wave transport. Here, we experimentally demonstrate a counterintuitive phenomenon where transport is enhanced by deliberately introduced dissipation in phononic crystal. The key to this phenomenon lies in the fact that a nonuniform dissipation texture reshapes both the real and imaginary parts of the classical wave dispersion, thereby closing the hybridization gap between two counterpropagating modes and thus enhancing transport. We experimentally verify this finding on a valley phononic crystal with two closely positioned valley kink state channels. When dissipation is added to one of the channels, it is observed that the hybridization gap is reduced and the sound decay in the other channel becomes smaller. Our results reveal the power of dissipation in controlling wave transport, and the proposed scheme is ready to be generalized to various wave devices where crosstalks occur.