High-Saturation Full-Color Printing with All-Dielectric Chiral Metasurfaces

Precise engineering of light–matter interactions has enabled a wide variety of approaches to create brilliant structural colors that overcome the limitation of pigments and dyes in sub-diffraction resolution, enhanced durability, and environmental friendliness. Techniques unitizing photonic crystals, surface plasmons, Mie resonances, or Fabry–Perot cavities have been extensively investigated for applications ranging from coloration, displays, sensors to security devices. However, creating high-saturation colors in the bright-field environment remains challenging owing to the critical requirement of high-index contrast or homogeneous environment. Here, a generic strategy is reported to generate high-saturation bright-field structural colors in the cross-polarization spectra with all-dielectric chiral metasurfaces consisting of arrays of TiO2 half-gammadion-shaped resonators. We experimentally demonstrate that vivid reflective structural colors can be achieved across the visible spectrum by carefully engineering the chiral resonators. It is shown that the reflectance at off-resonant wavelengths and higher-order resonances are strongly suppressed in the cross-polarization reflection spectrum, leading to extremely high-saturation color printing with a gamut larger than standard RGB (sRGB). Excellent color performance for sRGB tricolors is further demonstrated. The simple structure, facile fabrication, wide color gamut, and high saturation make the chiral structural colors competitive for polarization optical applications in micro-display, nanoprinting, anti-counterfeiting, data storage, and information encryption.