One-Dimensional Periodic Structures under a New Light

Abstract

Photonic crystals (PCs) are artificial dielectric media periodically microstructured in one, two or three spatial directions. The last decade of research efforts demonstrates that PCs are systems of strong scientific as well as industrial importance [1, 2, 3, 4]. The possibility to alter drastically the dispersion relation of photons is inherent to them. Three-dimensional (3D) PCs can exhibit energy gaps of zero density of photon states, i.e., full 3D photonic band gaps (PBGs). The control of the spontaneous emission should be possible in such periodic media [5, 6, 7]. At the same time, allowed bands of PCs display strong dispersion and spatial anisotropy, which lead to a number of new optical properties otherwise inconceivable in conventional crystals [8, 9, 10]. The strong dispersion and anisotropy of allowed bands are characteristic of any periodic structures even with a rather small refractive index contrast. This is a main difference with respect to a full PBG structure, which requires a special topology of a 3D dielectric lattice, as well as a considerably large refractive index contrast of constituents.