The fabrication and optical properties engineering of colloidal crystal heterostructures

Photonic crystal heterostructures are concatenations of photonic crystals differing in refractive index or lattice geometry. Colloidal crystal heterostructures can be made of different colloidal spheres. In this paper we present a method to fabricate such colloidal crystal heterostructures using successive deposition of colloidal spheres differing in diameter. Each layer of the crystal consists of a three-dimensionally ordered array of closed- packed colloidal spheres. The resulting colloidal crystal heterostructures exhibit optical properties which resemble the superposition of the properties of each individual crystal. The optical properties of such systems would present an entirely different way of tailoring the photonic properties of these colloidal crystal films. These heterostructures thus afford new opportunities for engineered photonic behavior.