Large omnidirectional band gaps and selective transmission in one-dimensional multilayer photonic structures

It has been shown that a one-dimensional periodic structure such as a super lattice can exhibit the property of omnidirectional reflection, which means that any incident wave launched from the vacuum (or from a substrate) will undergo a total reflection at the superlattice boundary, whatever the inci dent angle or the polarization of light is. In this communication, we show that large omnidirectional band gaps can be obtained by associating two or several superlattices in tandem. We discuss the existence conditions for th ese gaps as compared to the usual case of a binary superlattice. By introdu cing a defect layer in the finite layered structure, one can obtain localiz ed modes inside these omnidirectional band gaps, giving rise to the selecti ve transmission through the structure. These modes appear as peaks in the t ransmission spectrum with a very high quality factor, and therefore may hav e useful applications in the frame of photonic band-gap materials. (C) 2001 Elsevier Science Ltd. All rights reserved.