Nanophotonic Structural Colors

Structural colors traditionally refer to colors arising from the interaction of light with structures with periodicities on the order of the wavelength. Recently, the definition has been broadened to include colors arising from individual resonators that can be subwavelength in dimension, for example, plasmonic and dielectric nanoantennas. For instance, diverse metallic and dielectric nanostructure designs have been utilized to generate structural colors based on various physical phenomena, such as localized surface plasmon resonances (LSPRs), Mie resonances, thin-film Fabry-Pérot interference, and Rayleigh-Wood diffraction anomalies from 2D periodic lattices and photonic crystals. Here, we provide our perspective of the key application areas where structural colors really shine and other areas where more work is needed. We review major classes of materials and structures employed to generate structural coloration and highlight the main physical resonances involved. We discuss mechanisms to tune structural colors and review recent advances in dynamic structural colors. In the end, we propose the concept of a universal pixel that could be crucial in realizing next-generation displays based on nanophotonic structural colors.