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

We have developed a novel ceramic processing technique to fabricate photoni c crystals (PC's) with close-packed lattices of air pores in a dielectric b ackground. The ordering of colloidal spheres and incorporation of the titan ia is performed simultaneously, in contrast to other approaches. Excellent ordering of the lattice of air pores is achieved over domains extending ove r 100 mu. The PC's exhibit a uniform color and a corresponding sharp peak i n 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, pro viding strong evidence for photonic crystal effects.