Temporal Coupled Mode Analysis of Chromaticity in Trilayer Subtractive Structural Colors

We present a new way of understanding the spectral behaviorofa Fabry-Perot-type trilayer stack for a subtractive structuralcolor based on a temporal coupled mode analysis. This cavity-basedanalysis is able to fit reflection spectra feature and predict colorchromaticity well even without taking material dispersion into account.To produce the most chromatic color, this analysis reveals that matchingof absorptive and radiative decay rates while both being maximizedis the key, which leads to a broad and highest absorption peak. Inclusionof an ultrathin high-index dielectric on top of the lossy bottom layercan further boost the absorptive decay rate of the cavity, which helpsto fine-tune color chroma. Both simulation and experimental resultsare presented in accordance with color chromaticity predicted by thetemporal coupled mode analysis.