High saturation and extending color gamut of reflective structural color using SiO2-TiO2 double-layer all-dielectric metasurface

Abstract

Metallic nanostructures exhibit limitations in generating high-performance structural colors due to inherent ohmic losses and interband transitions. The elevated refractive index of dielectric materials can facilitate high-order Mie resonance at shorter wavelengths, leading to a decrease in color saturation. To overcome these challenges, this study employs the principle of surface lattice resonance to investigate the impact of various refractive index top layers on the reflection spectrum and to select appropriate coating materials. Develop a SiO₂-TiO${}_2$ double-layer disk array by integrating an all-dielectric metasurface on a SiO₂ substrate. We achieve high-performance structural colors characterized by a minimum bandwidth of less than 7 nm, reflectance levels reaching up to 99%, and saturation levels attaining 100% within the visible spectrum range of 400-700 nm. Moreover, by modifying the geometry of the SiO₂-TiO${}_2$ double-layer all-dielectric metamaterials, we successfully extend the color gamut to 168.2% sRGB and 124.6% Adobe RGB and 56.1% CIE color gamut space. The findings of this study present significant potential for applications in color display, data storage, and anti-counterfeiting technologies, offering empirical theoretical support for these domains.