Optical behaviour of sol-gel derived photonic structures formed by submicron silica spheres

Sol-gel synthesis of powders consisting of regularly shaped submicron silica spheres (?400-600 nm) is described. IR and absorption spectra of such powders have been obtained. The IR spectra demonstrate that the silica spheres heated at 800 ?C are hydroxyl-free. The TEM measurements show that the dimensions of silica nanoparticles do not change during heating. Films of self-organized silica nanospheres deposited on a glass support exhibit the photonic crystal effect.