单个金属纳米颗粒的散射特性分析

单个金属纳米颗粒的散射特性分析

摘要

本文第一章从表面等离激元入手，运用Drude模型解释了表面等离激元是如何产生的。并阐述了表面等离激元由于金属结构的不同而产生的两种分类：局域的表面等离激元和传导的表面等离激元。在第二章中，主要阐述3种理论模型，Mie模型、Drude模型以及Lorentz Drude模型，并对他们各自的优缺点、适用条件进行了简单的说明。第三章则是用COMSOL Multiphysics对单个金属纳米颗粒的散射特性进行仿真模拟，得到了不同尺寸（半径20、30、40、50、60nm）金球的吸收截面和散射截面曲线、并观测到了表面等离激元对光的选择性吸收和散射现象，以及吸收、散射峰的红移效应。最后也模拟了s偏振光和p偏振光以不同角度入射时金球的散射情况，可以发现s偏振光在有角度入射时的散射情况与垂直入射时基本一致，而p偏振光有角度入射时的散射情况与垂直入射时有很大的却别。得出的结果基本与理论一致，从而也验证了该仿真模拟的可行性。

关键词：表面等离激元，Mie模型，Drude模型，Lorentz Drude模型，散射截面，COMSOL Multiphysics仿真模拟

Study of single nano gold particle’s scattering characteristic

ABSTRACT

The first chapter of this thesis is started from surface plasmon, using the Drude model to interpret the production of the surface plasmon. And we show the two kinds of the surface plasmon, caused by the difference of the metal structure. The first is the localized surface plasmon and the second is the propagating surface plasmon polarization. Then we display Mie model,Drude model and Lorentz Drude model mainly in chapter 2, moreover gave an exhibition of the appliance of them. In the third chapter using COMSOL, we stimulate single nano gold particle's scattering characteristic and get the absorption cross section and scattering cross section curve of gold sphere with different sizes. Consequently, the selective absorption and scattering phenomena,and the red-shift of absorption,scattering peaks are both achieved in our experiments. Finally,we show gold sphere scattering properties with s- and p- polarization light incident at different angles. S polarization light was observed that it gave no difference at minor or normal incidence, while p polarization light showed distinct differences at any incident angles. We arrive at the same conclusion with theory, which confirms the availability of this stimulation.

KEY WORDS：surface plasmon,Mie model,Drude model,Lorents model,scattering cross section,COMSOL Multiphysics

目录

单个金属纳米颗粒的散射特性分析.............................................. I 摘要...................................................................... I Study of single nano gold particle’s scattering characteristic ............. II 前言. (1)

1 表面等离激元（surface plasmons，SPs） (2)

1.1 用Drude模型解释表面等离激元的产生 (2)

1.2 表面等离激元的分类 (3)

1.2.1 局域的表面等离激元 (3)

1.2.2 传导的表面等离激元 (4)

2 表面等离激元的解析计算与相应模型 (6)

2.1 Mie模型 (6)

2.2 Drude模型 (6)

2.3 Lorentz Drude模型 (8)

2.4 三种模型的适用情况及优缺点比较 (8)

3 COMSOL仿真模拟 (9)

3.1 COMSOL介绍 (9)

3.1.1 COMSOL Multiphysics发展历史 (9)

3.1.2 COMSOL Multiphysics适用模块 (9)

3.1.3 COMSOL Multiphysics的求解方式 (9)

3.2 Comsol仿真模拟：单个金属纳米颗粒的散射特性分析 (9)

3.2.1 几何模型建立 (9)

3.2.2 参数设置 (12)

3.2.3 模拟结果及分析 (15)

4 总结和展望 (22)

4.1 总结 (22)

4.2 工作展望 (22)

4.2.1 模拟的准确性 (22)

4.2.2 实验可行性 (23)

4.2.3 误差分析及改进 (23)

参考文献 (25)

致谢 (26)