Plasmonic color pixels fabricated by nanoimprint process

Plasmonic nanostructures or metasurfaces have recently been actively researched for structural color generation. Controlling the plasmonic resonant wavelengths of surface plasmon polaritons excited along the metal dielectric interfaces, arising from the resonant interaction with incident electromagnetic waves, reflection or transmission color can be effectively tuned in the visible wavelength region. However, the plasmonic structures are conventionally fabricated by electron beam lithography or focused ion beam, both so expensive and unproductive that they are not practical for large-scale production. In this report, we demonstrate a simple plasmonic nanostructure for various color generation fabricated by a quite simple and cost-effective method applying nanoimprint process and aluminum film deposition. We experimentally evaluated the reflectance spectra of the color pallets composed of the plasmonic nanostructures (plasmonic color pixels) and compared with the simulation results. We confirmed the wide-range tuning ability of reflection color by changing the size parameter of the plasmonic nanostructures. Therefore, this method for high-definitive color generation can be expected to be applied to a wide range of fields including various applications, such as security labels, anti-counterfeiting devices, information storage and functionalized decoration.