A Numerical Study On Metallic Photonic Crystal And Plasmonic Waveguides

There are great advances in photonics owing to the development of nano technology,a lots of topics have become focuses of research,such as Nanopho-tonics,Photoelectronics,photonic crystal,Metamaterials,negative refraction, and surface plasmons etc.A large variety of new structures and devices are developed as well.They are often too complicated to perform an analytical study,so numerical study is necessary to designer and it is cost saving than experiments.Focusing on numerical computing,a lots of original work have been done in the dissertation.1.ADE,PLRC,etc are approaches to dealing with dispersion media.Based on Drude modal,the discretized formula for each approach are given.2.The band gaps of several kinds of metallic photonic crystals are calculated, the relations between band gaps and structures(lattice constant(a)and filling fraction(f))are given.There is a cutoff frequency(ω_c)in 2D metallic photonic crystal(TM mode).When a>20μm,ω_c is out of relation to the type of metal,and only relate to a and f.The mathematical relationship between them is given.When lattice constant(a)is large than a critical size,the second band gap will appear.critical sizes are calculated for different types of metallic photonic crystals.The relation between gap width and f is calculated. When f≈0.6,the gap width reach it's maximum.3.Negative refraction can be implemented by photonic crystal,it is based on complex Bragg scattering effects.However,the effective index of photonic crystal is not necessarily negative,it also might be positive.By analyzing the EFS of photonic crystal,these two cases can be decerned.Several criterions are summarized in EFS analysis. ●The phase velocity(v_p)is the same direction as wave vector(k),the group velocity(v_g)is the same direction as Poynting vector(S).The case when v_g·k<0 denotes negative index,and v_g·k>0 denotes positive index.●At the interface,tangent components of k are equal.●v_g is perpendicular to EFS,and point to the direction of large fre-quency.●v_g is away from source.Beside these original works above,a lots of other works have been down.1.CPML is presented because it's advantages over other type of PML,it can efficiently absorb propagating mode as well as evanscent mode.There is barely no literature in Chinese.2.Electronic circuits provide us with the ability to control the transport and storage of electrons.However,the performance of electronic circuits is now becoming rather limited when digital information needs to be sent from one point to another.Optical interconnects such as fiber optic cables can carry digital data with a capacity>1000 times that of electronic interconnects.Unfortunately,fiber optic cables are～1000 times larger compared with electronic components.The discrepancy in size limits the integration of optical and electronic circuits.Surface plasmons provide the opportunity to confine light to nanoscale and might bridge Electronic circuits with optic circuits in the future.FDFD is suitable for analyzing all kinds of waveguides,including conventional optical fiber,photonic crystal fiber,and plasmonic waveguides as well.Several geometries of plasmonic waveguides and FDFD are discussed.