Plasmonic color filters inherently suffer from angular sensitiveness, which hinder them from practical applications. Here, we present a plasmonic subtractive color filter incorporating two-dimensional randomly distributed silver nanodisks on top of a glass substrate. Due to the elimination of structural periodicity, the proposed plasmonic color filter works via localized surface plasmon resonances (LSPRs) and thus enables excellent angle-insensitive (up to 60°) performance. In addition, uncoupled LSPRs between nanodisks guarantee stability and reproducibility of the color filter. Finally, a palette of colors across the visible region was obtained with the proposed color filters by simply varying the diameter of nanodisks, exhibiting a promising and robust applicability in digital imaging and sensing industries.

MOF-coated NHA plasmonic gas sensor with high sensitivity and temperature-induced analyte discrimination.

Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra.

The effects of film thickness and nanograting period on color filter behaviors of the device, fabricated by sub-micrometers patterning on plasmonic silver thin films, have been studied. It is found that color filter properties strongly correlate with film thickness and nanograting period. Based on obtained results, the relationship of the wavelength of transmission minima with film thickness and nanograting period was derived. This equation can predict the transmission minima for a given thickness and period in one-dimensional Ag metallic film nanograting on glass substrate, which could guide to design color filter device with desirable wavelength.