  Plasmonic color printing with semicontinuous metal films is a
lithography-free, non-fading, and environment-friendly method of generation of
bright colors. Such films are comprised of metal nanoparticles, which resonate
at different wavelengths upon light illumination depending on the size and
shape of the nanoparticles. To achieve an experimentally demonstrated structure
that was optimized in terms of broader color range and increased stability,
variable Ag semicontinuous metal films were deposited on a metallic mirror with
a sub-wavelength-thick dielectric spacer. Femtosecond laser post-processing was
then introduced to extend the color gamut through spectrally induced changes
from blue to green, red, and yellow. Long-term stability and durability of the
structures were addressed to enable non-fading colors with an optimized
overcoating dielectric layer. The thickness of the proposed designs is on the
order of 100 nanometers, and it can be deposited on any substrate. These
structures generate a broad range of long-lasting colors in reflection that can
be applied to real-life artistic or technological applications with a spatial
resolution on the order of 0.3 mm or less.
