Structural colors based on all-dielectric metasurfaces hold great promise for a wide range of applications, including high-density optical storage, ultra-high-resolution 3D displays, imaging security certification, and so on. However, achieving dynamic tunable structural color with a compact and simple Si platform remains a great challenge. Here, we propose a dynamic tunable structural coloration with polarization-sensitive metasurfaces consisting of arrays of Si elliptical nanopillars, enabling full-colored images to be displayed and switched through the control of the polarization of incident light. A distinct feature of our design is that the color phase is independent of the viewing angle, which is fundamental for real applications. Moreover, we demonstrated that dual and multiple colors can be obtained by varying the angle of either the polarizer or the analyzer. Our scheme provides a simple yet general approach for potential applications in the fields of virtual reality, ultra-high-resolution 3D displays, and high-density information storage.

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 “李龙杰” 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.

By combining a spiral zone plate (SZP) and a grating, we propose a single optical element, termed a composited spiral zone plate grating (CSZPG), to generate flower mode vortices with the equicohesive petals and has long focal depths. Theoretical analysis reveals that the CSZPG can generate flower mode vortices with approximately equicohesive petals, and that it has longer focal depths compared with the conventional SZP. Moreover, the performance of the CSZPG on the period, focal length and radius is investigated. The experimental results are also presented, agreeing well with the theoretical predictions. The unique characteristics of the proposed CSZPG make it attractive for many applications such as particle trapping and optical imaging.