Asymmetric acoustic splitting with the dual-layers of binary metagratings

Abstract

Here, we exhibit the asymmetric acoustic splitting with the dual-layers of binary metagratings (BMs), i.e., BM1 and BM2. For the positive incidence (PI) normally from the BM1 side, acoustic waves are freely transmitted through the BM1 and split into two beams with the transmitted angles at θt = 45º and θt =−45º, then the two beams are freely transmitted through the BM2 with the transmitted angles at θt =−45º and θt = 45º. For the negative incidence (NI) normally from the BM2 side, acoustic waves are wholly reflected. Hence, the asymmetric acoustic splitting is observed. Here, the dual-layers of BMs are exemplified by the coating cells with different period lengths. Excellent agreement can be observed between the numerical simulations and the theoretical analysis. Our proposal may be applied in noise control and acoustic communication. Keywords: Acoustic asymmetric splitting, binary metagrating