Angle-tolerant polarization tunable expanded reflected plasmonic color palettes

Plasmonic structural color generation using metal nanostructures holds great promise in anti-counterfeiting tags, information encryption, and color displays due to its chemical/mechanical stability and high spatial resolution. Most of the recently demonstrated metal nanostructures produce static plasmonic color pixels; however, more advanced optical applications such as information encryption require direct and reliable solutions to tune the plasmonic color pixels. Here, the polarization-tunable expanded plasmonic color pixels based on the combination of any two of three subtractive primary color modules in a subwavelength supercell are proposed. The plasmonic color pixels can achieve continuously expanded plasmonic color palettes between any two of three subtractive primary colors by varying the incident polarization angle and a wide color gamut covering 65 % of sRGB color space is also achieved. Meanwhile, benefiting from the strong confinement of the gap-surface plasmons, the plasmonic color pixels have a high angular tolerance of ∼45°. Furthermore, the color tuning between three subtractive primary colors and three additive primary colors can be achieved by introducing the approach of mixing colors. Such excellent performances open the avenue for security tags, full-color displays, and advanced optical encryptions.