Multi‐Dielectric Metasurfaces for Ultrabright, Tunable Structural Color and Reconfigurable Optical Filtering with Extraordinarily Large Color Span

ABSTRACT Color is a fundamental element of human perception, impacting emotional and behavioural responses, and color space serves as an essential metric in advanced optical imaging and display technologies. Here, we propose and experimentally demonstrate a multi‐dielectric metasurface architecture that enables bright, ultra‐saturated, superior color generation with unprecedentedly high reflectivity up to 93%. The proposed metastructure consists of multi‐layered truncated cones of gallium phosphide (GaP) sputtered between a pair of titanium dioxide (TiO 2 ) layers carefully constructed to induce both magnetic dipole (MD) and magnetic toroidal dipole (MTD) modes. The engineered design achieves a record experimental CIE 1931 color gamut of 222.1% in sRGB, 164.5% in Adobe RGB, and 117.4% in Rec. 2020. The pronounced dependence of the fabricated metastructures on their dielectric environment allows for exceptional color tunability across the visible spectrum via their thin film coating with consistently high reflectivity. Finally, as proof‐of‐concept demonstrations, we show reconfigurable, high‐performance filters and reflectors employing the same design framework by precisely tailoring the geometry of the metasurface. The proposed architecture paves a promising route toward next‐generation unexceptionally bright digital displays, printing technologies, and advanced photonic applications.