Integrated Dynamic Control of Plasmonic Bound States in the Continuum Enabled by Phase‐Change Sb 2 S 3

ABSTRACT Bound states in the continuum (BICs) demonstrate remarkable light confinement capabilities, yet exhibit high sensitivity to structural perturbations and static operational behavior, both of which limit their practical applicability. To address these challenges, in this work, a dynamically tunable BIC platform is constructed by integrating the phase‐change material Sb 2 S 3 with a plasmonic grating. Our approach overcomes the traditional trade‐offs between stability and tunability through nonvolatile phase transitions that simultaneously control three key BIC properties: a substantial resonance wavelength shift of over 100 nm, a remarkably widened angular operating range for high‐Q phenomena, and controllable band dispersion. These tunable functionalities, enabled by the material's phase transition, render the platform highly suitable for devices that leverage enhanced light–matter interactions, slow‐light effects, and wide‐field imaging. Specifically, such a tunable BIC‐metasurface results in distinct transfer functions in the spatial frequency domain before and after the phase transition, which endows the device with the capability of active frequency control. Numerical simulations demonstrate that the structure can function as an effective image denoiser. This not only overcomes the fundamental limitations in the dynamic modulation of BICs but also establishes a new pathway for developing multifunctional metasurface devices with on‐demand resonance engineering.