Acoustic adiabatic transfer through chirped detuning of supermodes

Coherent control via laser pulses, including stimulated Raman adiabatic passage and rapid adiabatic passage, has been extensively studied for robust and selective population transfer of quantum states. Notably, the classical analog of stimulated Raman adiabatic passage has been successfully implemented in optical and acoustic wave transfers within waveguide systems. In this study, we numerically and experimentally investigate the adiabatic transfer of acoustic waves in a composite waveguide structure that serves as the acoustic analog of a quantum rapid adiabatic passage. The composite waveguide structure consists of two waveguide units and supports two odd-symmetric supermodes. The supermode propagation constant can be modulated by adjusting the coupling strength between the paired waveguides within each individual waveguide unit. Under a constant detuning of the supermode propagation constants, the adiabatic passage results in a complete return of acoustic waves in the excited waveguide unit. In the case of chirped detuning, an adiabatic transfer of acoustic waves from the excited waveguide unit to another one is achieved. Our proposal presents opportunities for anomalous manipulation of acoustic waves, which may have potential applications in wave splitting, focusing, and mode conversion.