Plasmonic- and dielectric-based structural coloring: from fundamentals to practical applications

a Schematics of cross-shaped PCFs (SA short arm, LA long arm. The average dimensions of aperture are w = 30 ± 2 nm, P = 340 nm, SA = 120 ± 5 nm and LA = 203 ± 3 nm. b Color palette with variation in polarization. (i) Colors transmitted through the LA resulting from polarization along the SA. (ii) Colors transmitted through the SA resulting from polarization along the LA. c Micrographs of butterfly with wing color variations, when polarized along SA (i) and LA (ii) [52]. d Color distributions simulated in CIE 1931 chromaticity diagram with (i) Ag (ii) Al and (iii) Au. e Two-step fabrication composed of nanoimprint and metal deposition. f (top) Transmissive microscopic color palette using Ag. (bottom) Three scanning electron microscope (SEM) images of nanohole pixels with 500-nm periodicity and exposure to e-beam dose of 900 (left), 720 (middle) and 500 (right) μC/cm2, corresponding to red, yellow and white circles of top image [53