Effect of disorder on photonic band gaps

We study the transmission of electromagnetic waves propagating in three-dim ensional disordered photonic crystals that are periodic on the average with a diamond symmetry. The transmission has been calculated using the transfe r matrix method. We study two different geometries for the scatterers: sphe res and rods connecting nearest neighbors. We find that the gaps of the per iodic structure survive to a higher amount of disorder in the rods' case th an in the spheres' case. We argue that this is due to the connectivity of t he rod structure that exists for any amount of disorder. [S0163-1829(99)041 20-X].