Fabrication of three-dimensional photonic crystals for use in the spectralregion from ultraviolet to near-infrared

This paper describes a simple and convenient method that allows self-assemb ly of colloidal particles (50 nm-50 mu m in diameter) into cubic-close-pack ed (c.c.p.) lattices over areas larger than 1 cm(2). These three-dimensiona l (3-D) lattices have a highly ordered structure similar to that of a natur al opal, with a packing density of approximately 74%. They strongly diffrac t light, and each of them exhibits a stop band whose position is mainly det ermined by the size of the particles. These crystalline assemblies of parti cles have also been used as templates to fabricate inverse opals, that is, three-dimensionally porous membranes consisting of a c.c.p. lattice of inte rconnected air balls. Both types of periodic structures are potentially use ful as 3-D photonic bandgap (PBG) crystals that can be used to control the emission and propagation of light in the spectral region ranging from ultra violet (UV) to near infrared.