Configurationally Tunable Mie, Plasmonic and Diffractive Structural Colors in a Single Design

We have developed a structural color design capable of displaying Mie resonant, plasmonic, and diffractive colors within a single design, depending on the configuration of imaging setup. Previous research achieved two distinct colors arising from the same resonance mechanism by introducing anisotropy into the structural parameters of a 2D array and selectively displaying each color based on the polarization. In this study, however, we store and display multiple colors within a single design by employing a 1D metallodielectric grating composed of TiO_x nanowires sandwiched between two Ag layers. Choice of polarization allows for either an electric dipole Mie resonance or a localized surface plasmon resonance to occur independently, generating striking differences in color. Furthermore, the selection of numerical aperture (NA) can further extend the color modulation, as collected diffracted light wavelength is determined by the NA. We also demonstrate the color modes from the 1^st order diffraction. All resonance mechanisms and imaging configurations depend solely on the two spatial parameters and their combination: the period and the width of the nanowire. Finally, we demonstrate four levels of encoded images produced from a single set of the gratings under different imaging setups. These findings open up new possibilities for applications, such as image encryption and data storage, and so on.