Anisotropy-induced acoustic unidirectional guided resonances
Phys. Rev. B 113, 054114 – Published 23 February, 2026
DOI: https://doi.org/10.1103/d5sg-9dhv
Abstract
Unidirectional acoustic radiation from underwater structures holds significant potential for diverse applications, such as highly directional emission, target detection, and recognition. In this work, we theoretically propose a novel mechanism based on a two-dimensional anisotropic waveguide structure with two radiating channels toward water, which affords anisotropy-induced unidirectional guided resonances (UGRs), in which acoustic radiation is canceled in one of the channels and redirected into the other. We show that the UGRs emerge from the bound states in the continuum when the vertical mirror symmetry is broken by rotating the principal axes of the anisotropic material, and guided by this mechanism, we achieve high up-down radiation ratio. Moreover, we apply temporal coupled mode theory to reveal a unique all-pass acoustic phase-shifting behavior enabled by the UGRs. The proposed anisotropy-induced acoustic UGR mechanism opens new avenues for designing highly directional radiators and phase-shifting devices.
