典型纳米结构非局域化光学特性研究

发布时间：2018-03-26 06:25

  本文选题：等离子体　切入点：纳米结构　出处：《安徽大学》2015年硕士论文

【摘要】：随着科学技术和实验技术的发展,纳米结构材料的可加工,纳米结构因其表面特有的表面等离激元特性而越来越受到人们的关注。尤其纳米结构的表面等离子体能反应其光学特性。在外加激励源情形下,金属中的自由电子与空气表面发生共振而引起表面等离激元(SPP)。而等离子体光学就是基于金属纳米结构中传导电子与电磁辐射交互作用而引起的一种低于波长尺度的近场光学增强效应。在实际应用中如太阳能电池,由于金属特殊的光学特性,能够在一定条件下激励出表面等离子体激元引起共振现象,通过改变金属薄膜厚度、周围介质和金属的周期性结构等参数,都可以大幅度提高纳米薄膜的电磁透射效率。在其他方面其应用也越来越广泛,例如在生物传感器、近场显微技术和表面局域和近场增强特性,超分辨成像以及纳米级的光电器件制造等领域。本文的研究工作主要是围绕基于表面等离子体共振,在不同的贵金属纳米结构的表面产生的局域和非局域化光学特性。本文主要分为以下三个内容：首先介绍研究的背景,并介绍了表面等离子体和纳米结构的光学特性参数等基本理论概念。其次主要介绍了计算贵金属纳米结构光学特性的数值仿真算法,着重介绍了时域有限差分算法(FDTD)的基本原理和基本方法。引入了模拟贵金属介电常数的几种模型,通过采用Drude和Lorentz模型,对贵金属的介电常数进行拟合。介绍了贵金属纳米结构的局域(local)和非局域(nonlocal)的特性。结合FDTD算法,在不同介电常数模型下,得到了电场和磁场的具体差分公式,并利用后处理技术得出吸收截面、散射截面和消光截面。最后主要研究不同结构下贵金属纳米结构的local和nonlocal性质。首先研究了不同厚度下的金属薄膜的传输、反射和吸收特性；其次讨论不同纳米线结构和柱纳米线和三角形纳米线之间耦合下的local和nonlocal特性；最后讨论核壳模型下,不同尺寸和周围介质对贵金属纳米结构消光截面的影响。
[Abstract]:With the development of science and technology and experimental technology, nanostructured materials can be machined. Nanostructures have attracted more and more attention because of their unique surface isophosphoric properties, especially the surface plasmas of nanostructures can reflect their optical properties. In the case of external excitation sources, the surface plasmas of nanostructures can reflect their optical properties. The resonance between free electrons in metal and air surface leads to the surface isotherm SPP. The plasma optics is based on the interaction between conducting electrons and electromagnetic radiation in metal nanostructures, which is a kind of lower wavelength scale caused by the interaction of electron conduction and electromagnetic radiation in metal nanostructures. In practical applications such as solar cells, Because of the special optical properties of metal, the surface plasmon excitation can induce resonance under certain conditions. By changing the thickness of the metal film, the periodic structure of the surrounding medium and the metal, and so on, Can greatly improve the electromagnetic transmission efficiency of nanocrystalline films, and are also increasingly used in other areas, such as biosensors, near-field microscopy and surface local and near-field enhancement properties, Super-resolution imaging and the fabrication of nano-scale optoelectronic devices. The research work in this paper is mainly based on surface plasmon resonance (SPR). The localized and nonlocalized optical properties on the surface of different noble metal nanostructures. This paper is divided into the following three parts: firstly, the background of the study is introduced. The basic theoretical concepts such as surface plasma and optical characteristic parameters of nanostructures are introduced. Secondly, numerical simulation algorithms for calculating optical properties of noble metal nanostructures are introduced. This paper introduces the basic principle and method of FDTD algorithm, introduces several models to simulate the dielectric constant of noble metals, and adopts Drude and Lorentz models. The dielectric constant of noble metals is fitted. The local and nonlocal properties of noble metal nanostructures are introduced. Based on the FDTD algorithm, the differential formulas of electric field and magnetic field are obtained under different dielectric constant models. Finally, the local and nonlocal properties of noble metal nanostructures under different structures are studied. Firstly, the transmission, reflection and absorption characteristics of metal films with different thickness are studied. Secondly, the characteristics of local and nonlocal under the coupling of different nanowires and column nanowires and triangular nanowires are discussed. Finally, the effects of different sizes and surrounding media on the extinction cross sections of noble metal nanostructures under the core-shell model are discussed.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
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本文编号：1666722