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Surface Plasmon Transmission Property In Metal-Dieletric-Metal Structure

Posted on:2012-04-08Degree:MasterType:Thesis
Country:ChinaCandidate:Y XuFull Text:PDF
GTID:2218330362451659Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
Plasmonics waves are a special kind of surface electromagnetic fields which are strongly confined to the interface of noble metal and dielectric materials. They are capable of being guided and transported in the subwavelength (sub-100nm) scale. Recently, plasmonic waveguides have attracted considerable attention and gradually become the hot pot of foundation and application because they can be applied to photonic integrated circuits. A variety of metallic structures have been proposed as waveguides among which metal-dielectric-metal (MDM) plasmonic waveguides are considered to have unique advantages. Compared with other waveguides, it is more compact, smaller and easier to be integrated into optical circuits. In this thesis, we study the transmission characteristics of surface plasmons in MDM waveguide and propose several special plasmonic elements based on it to realize plasmon control in nano-scale.Firstly, we combine analysis of the theory and simulation to investigate the modulation of the transmission characteristics of surface plasmons in MDM waveguide by changing the geometry size, the wavelength and the structure details. Particularly, a cavity is constructed by placing a defect in the periodic structure of MDM waveguide to realize the enhancement and localization characteristics of the local field in the surface plasmon nanocavities. The finite-element numerical results by using the software of COMSOL Multiphysics reveal that the propagation direction and distance of the surface plasmons can be controlled by changing the dielectrics, such as its thickness and dielectric constant, by making periodic surface pattern on it , and/or by constructing a tooth shaped waveguide, etc.Secondly, we focus on the tooth shaped MDM waveguides, and study their wave filter characteristics which are strongly depended on the width and depth of the tooth. In addition to the numerical simulation, the scattering matrix theory is used to establish a transmission model. We further combine the scattering matrix theory and coupled resonance cavity theory and derive the transmittance expression,and then obtain a transmission rate curve between transmission rate and wavelength. All results show that when the depth of the tooth shaped waveguide satisfies constructive interference,the plasmonic wave cannot be transmitted, so we can use this structure to realize a subwavelength filter.This study paves a foundation to design broad-band plasmonic waveguides.
Keywords/Search Tags:Surface plasmon polaritons, MDM waveguide, subwavelength scale waveguide, tooth-shaped waveguide, FEM
PDF Full Text Request
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