Optical photonic crystals fabricated from colloidal systems

Photonic crystals of close-packed arrays of air spheres in a dielectric bac kground of titania have been fabricated with a ceramic technique. Unlike pr evious methods, ordering of the spheres and the formation of the titania ne twork are performed simultaneously. The photonic crystals exhibit a reflect ance peak and a uniform color at the position of the first stop band. The w avelength of the reflectance peak scales very well with the sphere size. (C ) 1999 American Institute of Physics. [S0003-6951(99)04526-X].