基于偶极子—自洽场理论的近场光学显微术研究
文献类型：学位论文
| 作者 | 武清华 |
| 学位类别 | 硕士 |
| 答辩日期 | 2002 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐至展 |
| 关键词 | 近场光学显微镜 场传播子 偶极子—自洽场理论 系统分辨率 偶极子 偏振特性 |
| 其他题名 | Study on scanning near-field optical microscopy based on dipole-self-consistent field theory |
| 中文摘要 | 该论文首先阐述了近场光学显微镜的基本结构和装置及其应用与发展,然后从整体上介绍了用于近场光学成像研究的各种理论.比较而言,微观偶极子模型能直观地表示近场光学显微镜中样品与探针的微结构,并有效地描述近场区域光场与物质的相互作用,所以我们采用了偶极子-自洽场理论研究近场成像的一般特性和偏振特性.这些研究对于解释和重构图像尤其是选择最佳系统参数是很有用处的.该论文的主要创新点是:1、发展了用于近场光学显微术研究的偶极子-自洽场理论,并运用该理论解释了近场光学显微镜中的共振现象,分析了共振现象发生的频率条件,这为实验观察提供了理论的依据.2、定义了近场光学显微镜的系统分辨率,详细地分析了影响系统分辨率的相关因素,包括探针的大小,探针与样品间的距离、不同偏振光照明等对系统分辨率的影响等.这些结论充分地说明了近场光学显微镜扫描成像的一般规律.3、论述了反射式近场光学显微镜中中场、远场传播子对所成光学图像的影响和作用.分析结果表明,近场与远场没有明确的界限,其间存在一个中场区域(100nm左右).在此区域,近场传播子已经不能有效地表示光场的传播及其与物质的相互作用,而需考虑到中场甚至远场传播子的贡献.所得的光学图像是光场中的近场成分与中场成分相互干涉叠加的结果,这样近场中的部分超分辨信息能够传至中场区域,从而可以在中场区域探测获得超分辨光学成像.4、详细地分析了不同偏振光照明对近场光学显微镜成像结果的影响.计算结果说明用z-方向偏振光照明能得到分辨率和局域性优于相应的x-偏振光照明的光学图像.且用x-偏振光照明成像时,所得的光学图像对比度将发生反转. |
| 英文摘要 | Scanning near-field optical microscopy (SNOM) can detect the evanescent wave to image, and its resolution exceeds greatly the optical diffraction limit. But there are many factors which influence the image by SNOM, so it is complex and difficult to explain correctly the image. It's necessary to study the rules of near-field imaging based on theory. In this dissertation, the basic structure and models of scanning near-field optical microscopy are described. SNOM's application and development are also presented. Then several theories used to research SNOM are discussed. In comparison, the microscopic dipole model can denote intuitively the object's microstructure, and describe availably the interaction between light field and objects. So we use the dipole-self-consistent theory to research the image character and the polarization effect of SNOM. These researched results are useful for interpreting and reconstructing the image, especially for optimizing the SNOM system parameters. Innovation of this dissertation includes: The dipole-self-consistent theory used to research SNOM is developed, and the resonance in SNOM is explained by this theory. We analyze the frequency condition with the resonance happening, which gives the foundation for observing the resonance in SNOM experiment. The system resolution of SNOM is defined. The factors influencing the system resolution are studied, such as the size of the probe, the distance between the probe and sample, and the polarization of incident light. These' conclusions reveal the general rules of SNOM. In reflection mode SNOM, the contribution and influence of the middle field and far field propagator on the imaging is dissertated. The analysis results show that there is a middle field region about 100 nm between near field and far field region. In the middle field region, near field propagator is not available for describing the interaction between the light field and objects, it is necessary to consider the contribution of middle and far propagator. The imaging is the result of the near field component and middle field component interference, thus the near field super-resolution information is extended to the middle field region so that it is possible to obtain the super-resolution imaging in the middle field region. 4. The influence of the polarization of incident light on the imaging quality of SNOM is analyzed. The calculating result shows the system resolution and localization are better when the incident light is polarized vertically to the surface (via z-axis polarized) than when it is horizontally polarized. When the incident light is x-axis polarized, the imaging achieved by scanning the object can reverse locally in contrast. In addition, the intensity distribution of all components of light field is studied, which reveals the polarization effect of the optical near field. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16615]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 武清华. 基于偶极子—自洽场理论的近场光学显微术研究[D]. 中国科学院上海光学精密机械研究所. 2002. |
入库方式： OAI收割
来源：上海光学精密机械研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。