Optical photonic crystals synthesized from colloidal systems of polystyrene spheres and nanocrystalline titania

We have developed a novel ceramic processing technique to fabricate photonic crystals (PC's) with close-packed lattices of air pores in a dielectric background. The ordering of colloidal spheres and incorporation of the titania is performed simultaneously, in contrast to other approaches. Excellent ordering of the lattice of air pores is achieved over domains extending over 100 mu. The PC's exhibit a uniform color and a corresponding sharp peak in the reflectivity at the wavelength of the first stopband. The position of the reflectivity peak scales very well with the size of the air pores, providing strong evidence for photonic crystal effects.