Dynamic Polarization Flipping via Multimode Coupling Modulation in Composite Resonant Metasurface

ABSTRACT

This study proposes a polarization angle‐independent composite metasurface that enables dynamic and efficient polarization manipulation. Coupling pillars are introduced between the unit cells of a polarization converter, allowing both the inter‐structural coupling strength and the coupling mode configuration to be controlled by varying the pillar dimensions, thereby regulating the cross‐polarized and co‐polarized transmission. This coupling mechanism is accurately characterized using coupled‐mode theory. Numerical simulations validate that, owing to the optimization enabled by the coupling pillars, the cross‐polarization transmission coefficient of the converter increases by 6.4%, while the bandwidth expands by 167% compared with the unmodulated structure. Furthermore, simply by adjusting the pillar radius, the resonant peaks of the cross‐ and co‐polarization transmission coefficients can converge, leading to a complete polarization state flipping. Correspondingly, the equivalent coupling mode shifts from a three‐mode to a four‐mode configuration. Integrating the phase‐change material VO ₂ into the coupling structure enables temperature‐triggered dynamic polarization switching, offering a novel strategy for reconfigurable metasurface design.