Theoretical Studies Of One-dimensional Metal / Dielectric Photonic Crystals

Photonic Crystals(PCs) are artificial materials with a periodic modulation in the dielectric constant which can create a range of forbidden frequencies called a photonic band gap(PBG).Photons with frequencies within the band gap cannot propagate through the medium. This unique feature can alter dramatically the properties of light,enabling control of spontaneous emission in quantum devices and light manipulation for photonic information technology.Photonic band-dap structures can also be found in nature,and they explain the color diversity of some of the living creatures.In this thesis,the propagation properties of electromagnetic waves in one-dimensional(1D) metallic-dielectric photonic crystals(MDPC) are studied theoretically.The thesis consists of four chapters.In the first chapter,the basic conception,the recent research progress and the fabrications of PCs are summarized,including the applications of the unique properties of PCs.In the second chapter,theoretical methods for PCs are presented. The transfer matrix method and the finite-difference time-domain method are discussed in brief.In the third chapter,the photonic band structures of 1D MDPCs are studied theoretically.We show that a 1D MDPC can be considered as an effective metallic medium with a well-defined effective plasma frequency. Many interesting properties such as the relationship between the effective plasma frequency and the optical thickness of the dielectric layers are presented by photonic band calculations and field distribution analysis. This effective plasma frequency is found to be inversely proportional to the optical thickness of the dielectric layer and is independent of either the constituent metal or the thickness of the metallic layer.By increasing the optical thickness of the dielectric layer the effective plasma frequency of a 1D MDPC can be depressed into extremely low frequencies such as far infrared or even below.In the fourth chapter,the properties of complete PBGs in 1D MDPCs are studied theoretically.Complete PBGs for TM Waves are founded in the 1D MDPCs for the first time.We show that the necessary condition which can lead to a complete PBG lies in the existence of surface waves in 1D periodic structures.Thus,complete PBGs also exist in a single-negative(negative permittivity or negative permeability) metamaterial.Base on a three-layer structure,a complete PBG for both TE and TM waves can be achievable.