Lithography-Free Plasmonic Color Printing with Femtosecond Laser on Semicontinuous Silver Films

Plasmonic color printing with semicontinuous metal films is a lithography-free and environment-friendly method for generating nonfading bright colors. Such films are comprised of islands, metal nanoparticles and their clusters of various dimensions, which resonate at different wavelengths upon external light illumination, depending on the size and shape of the local particle structures. To experimentally realize systems that were optimized for achieving a broad color range and increased stability, various silver semicontinuous metal films were deposited on a metallic (Ag) mirror with a subwavelength-thick dielectric (SiO2) spacer. Femtosecond laser postprocessing was then introduced to extend the color gamut, through spectrally induced changes, from blue to red and yellow. Long-term stability and durability of the structures were addressed to enable nonfading colors with an optimized overcoating dielectric layer. The thickness of the proposed design is on the order of 100 nm, 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.