Functional acoustic metamaterial using shortcut to adiabatic passage in acoustic waveguide couplers

Shortcut to adiabatic passage (STAP), initially proposed to accelerate adiabatic quantum state transfer, has been widely explored and applied in quantum optics and integrated optics. Here we bring STAP into the field of acoustics to design compact couplers and functional metamaterial. The space-varying coupling strengths of acoustic waveguides (WGs) are tailored by means of dressed states in a three-level system, accounting for the desirable acoustic energy transfer among three WGs with short length. We show that the acoustic coupler has one-way feature when loss is introduced into the intermediate WG. More uniquely, when the propagation of acoustic wave is designed to mimic a Hadamard transformation, an acoustic metamaterial can be constructed by arraying several couplers, possessing the beam-splitting function and unidirectional, broadband performances. Our work bridges STAP and the acoustic coupler as well as metamaterial, which may have profound impacts on exploring quantum technologies for promoting advanced acoustic devices.