Acoustic Reconfigurable Metagratings with High Quality Factor for Anomalous Wavefront Control

Acoustic resonance metasurfaces have emerged as versatile platforms for precise manipulation of acoustic waves, yet existing designs suffer from fundamental trade-offs among reconfigurability, structural complexity, and resonance quality factors (Q). Here, we theoretically propose and experimentally demonstrate a structural design of acoustic reconfigurable metagratings (ARMs) that achieves a high-Q Fano resonance via transverse translation of a tunable baffle. This mechanism is ensured by dynamic coupling between discrete local dark modes (first-order guided modes) and continuous bright modes (fundamental guided modes) confined within grooves to create pronounced Fano resonance. In contrast to traditional static metagratings, this device enables reversible switching between the state of perfect specular reflection and anomalous reflection using only a subwavelength displacement of tunable baffle. Furthermore, we analytically elucidate the mechanism of Fano resonance in ARMs and derive the expression for the resonance condition. All theoretical predictions are rigorously validated through full-wave simulations and experimental measurements. This work establishes a paradigm for designing high-Q acoustic components with tunable functionality, opening new avenues for applications in ultrasonic sensing and information processing.