Three-dimensionally periodic dielectric layered structure with omnidirectional photonic band gap

A three-dimensionally periodic dielectric structure with a large complete p hotonic band gap (PBG) is presented. The structure is distinguished by a se quence of planar layers, identical except for a horizontal offset, and repe ating every three layers to form an fcc lattice. The layers can be thought of as an alternating stack of the two basic two-dimensional (2D) PBG slab g eometries: rods in air and air cylinders in dielectric. These high-symmetry planar cross-sections should simplify the integration of optical devices a nd components by allowing modification of only a single layer, using simple defects of the same form as in the corresponding 2D systems. A process for fabricating the structure with conventional planar microfabrication techno logy is described. Gaps of over 21% are obtained for Si/air substrates. Rea sonable gaps, over 8%, can be achieved even for the moderate index ratio of 2.45 (Si/SiO2). (C) 2000 American Institute of Physics. [S0003-6951(00)008 48-2].