表面等离激元波导特性分析及其应用研究

发布时间：2018-02-27 02:34

本文关键词： 等离激元波导波导耦合非线性效应共振腔石墨烯泰伯效应光开关　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：表面等离激元是指纳米尺寸下由光波与金属表面自由电子相耦合产生的在金属-介质界面传播的横磁电磁波,具有高模式体积的模式,能够突破衍射极限,为实现纳米量级尺寸下光操纵开拓了一种新途径。同时石墨烯作为一种典型的二维材料,具有特殊的电学、光学等性质,太赫兹波段石墨烯可以激发表面等离激元,并且具有更强的约束能力和更低的损耗。本文分别以金属、石墨烯为传输介质设计了表面等离激元波导、圆盘谐振腔和阵列波导,研究并分析了波导耦合特性、圆盘谐振特性以及周期成像等光学现象。本文主要的研究内容如下:(1)介绍了表面等离激元的研究背景、研究现状及其主要特性。(2)介绍了金属的自由电子气Drude模型、表面等离激元的激发方式,以及本论文研究工作中用到的研究方法:有限元算法,(3)设计了一种新型的球冠型混合等离激元波导,研究了等离激元波导中的局域特性以及传输强度。研究结果表明所设计的混合型等离激元波导具有更强的局域性和较长的传输距离。(4)设计了一种带有金属帽的混合型表面等离激元波导结构,通过分析波导的有效面积Aeff、传播长度Lp、非线性系数γ、非线性品质因子F与波导参数及非线性材料的关系,得出所设计波导的最优参数及最佳的非线性材料。(5)设计了一种含有两个纳米盘谐振腔的等离激元滤波器,根据圆盘共振理论以及波导耦合理论,分析了共振波长、传输效率与波导参数之间的关系,结果表明滤波器的共振波长可以通过圆盘直径(r1、r2)调节,传输效率可以通过波导与圆盘的间隔(d)调节。(6)简要介绍了石墨烯特性,及其石墨烯表面等离激元的研究现状。设计了一种新颖的石墨烯表面等离激元波导结构,分析了所设计波导的有效折射率、传输距离、截止波长与波导参数之间的关系,并在此基础上设计了一种可调的光开关结构,分析了其传输性能,结果显示所设计的光开关结构在不同的费米能级下可以实现不同的开关状态。(7)设计了一种石墨烯表面等离激元波导阵列结构,对其模式及传播常数进行了详尽的分析,并基于超模耦合理论引入阵列波导中不同高阶模相加的理论,实现了石墨烯表面等离激元阵列中的泰伯效应,并从理论、模拟上详细分析了石墨烯能级、波导间隔与泰伯距离之间的关系,研究结果表明仿真结果与理论计算一致,验证了文中所提出的不同不同高阶模相加理论。这对未来石墨烯在自成像领域具有很高的应用价值。
[Abstract]:Surface isotherm is a transverse magnetic electromagnetic wave generated by coupling light wave with free electron on metal surface at nanometer size. It has a high mode volume mode and can break through the diffraction limit. As a typical two-dimensional material, graphene has special electrical and optical properties. Terahertz band graphene can excite surface isotherms. In this paper, we have designed the surface isobaric waveguide, disk resonator cavity and arrayed waveguide with metal and graphene as transmission media, and studied and analyzed the coupling characteristics of the waveguide. The main contents of this paper are as follows: (1) the research background of surface isopherons is introduced, and the present research status and its main characteristics. (2) the free electron gas (Drude) model of metals is introduced. In this paper, a new type of spherical crown waveguide is designed, which is the excitation mode of surface isopherons and the research method used in this paper: the finite element method (FEA), the finite element method (FEA), is used to design a new type of spherical crown mixed isoexcitator waveguide. The local characteristics and transmission intensity of the isobaric waveguide are studied. The results show that the hybrid waveguide has stronger localization and longer transmission distance. (4) A hybrid waveguide with a metal cap is designed. Conjunctive surface isophosphoric waveguide structure, The relationship between effective area, propagation length, nonlinear coefficient 纬, nonlinear quality factor F and waveguide parameters and nonlinear material is analyzed. The optimal parameters of the designed waveguide and the best nonlinear material are obtained. A kind of isolator filter with two nano-disk resonators is designed. According to the disk resonance theory and the waveguide coupling theory, the resonant wavelength is analyzed. The relationship between transmission efficiency and waveguide parameters shows that the resonant wavelength of the filter can be adjusted by the diameter of the disk, and the transmission efficiency can be adjusted by the spacing between the waveguide and the disk. In this paper, a novel structure of graphene surface isophosphor waveguide is designed, and the relationship between effective refractive index, propagation distance, cutoff wavelength and waveguide parameters is analyzed. On this basis, an adjustable optical switch structure is designed, and its transmission performance is analyzed. The results show that the designed optical switch structure can realize different switching states at different Fermi energy levels. A graphene surface isopultionic waveguide array structure is designed and its mode and propagation constant are analyzed in detail. Based on the supermode coupling theory, the theory of adding different higher-order modes in arrayed waveguides is introduced to realize the Tiber effect in graphene surface isophosphoric element array, and the graphene energy levels are analyzed in detail theoretically and numerically. The results show that the simulation results are in agreement with the theoretical calculation and verify the different higher-order mode addition theories proposed in this paper. This is of great value for the future application of graphene in the field of self-imaging.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN25;O441.4

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