Experimental Demonstration of an Acoustic Asymmetric Diffraction Grating Based on Passive Parity-Time-Symmetric Medium

Acoustic asymmetric transport is important for noise control and communication acoustics. Recent progress on non-Hermitian systems has yielded a scheme to realize asymmetric transport without nonlinear effects or mode conversion. The authors report the experimental realization of an asymmetric diffraction grating based on a cleverly designed passive $P\phantom{\rule{0}{0ex}}T$-symmetric medium, in which loss is introduced as an extra modulation factor, and the energy distribution can be adjusted more freely. Moreover, the designed structure is helpful for further research on non-Hermitian acoustic systems.