Coloring of aluminum using photonic crystals of porous alumina with electrodeposited Ag

Optical characteristics of the silver deposited photonic crystals of alumina film are investigated. The coloring of aluminum is due to the diffraction of the photonic crystal and the color is visualized because that the absorption of the silver nanoparticles suppresses the reflection from film/Al interface. The reflection and transmission spectra of the silver deposited photonic crystals with or without Al substrate are discussed together with the chromaticity coordinates. The silver deposited photonic crystal of alumina film has great potential on the coloring of aluminum.