Full-Color and Anti-Counterfeit Printings with All-Dielectric Chiral Metasurfaces

Structural color is a vibrant color produced by optical effects such as interference, diffraction, or scattering of incident light interacting with the nanostructure, which has the advantages of environmental protection, high saturation, and high resolution. High saturation and dynamic tunability are the current research hotspots for structural color. We achieve full-color wide gamut structural colors and anti-counterfeit functions by an all-dielectric chiral metasurface consisting of half-gammadion-shaped resonators embedded in PMMA and a top TiO2 layer on quartz coated with an ITO layer. This research has significant implications in micro-display, nano-printing, anti-counterfeiting, and information encryption. Structural color is anticipated to replace pigmented or chemical color due to its superior saturation, resolution, environmental friendliness, and longevity. We achieve a full-color gamut of structural colors and anti-counterfeit functions by an all-dielectric chiral metasurface consisting of half-gammadion-shaped resonators embedded in PMMA and a top TiO2 layer on quartz coated with an ITO layer. The prominent resonance peaks of this embedded chiral metasurface under the cross-polarization condition, which are provided by the polarization conversion features of the chiral structure, lead to extremely saturated structural colors. The color phase mainly depends on the structure's period, opening up a full-color range well beyond sRGB. Especially, we demonstrate a star with hidden information of the letter "A" and the Chinese word " " by taking advantage of the difference in the color phase change under different polarization conditions to decode the information, thus realizing the anti-counterfeiting function. Our proposed embedded chiral metasurface provides dual-function structural colors and is highly promising for micro-display, nanoprinting, anti-counterfeiting, data storage, and information encryption.