基于表面等离激元的光镊与拉曼增强技术研究

发布时间：2018-01-08 15:25

本文关键词：基于表面等离激元的光镊与拉曼增强技术研究　出处：《深圳大学》2017年硕士论文　论文类型：学位论文

【摘要】：表面等离激元(Surface Plasmon Polariton,SPP)是金属表面自由电子与入射光子相互耦合、集体振荡产生的表面电磁共振模式。由于SPP具有的表面电场局域、增强等特性,使其在SPP光镊操控、表面增强拉曼散射、SPP纳米刻蚀以及超分辨显微成像等领域取得令人瞩目的研究成果。表面等离激元场与金属纳米结构相互作用时,会使电磁场高度局域并产生增强效果。SPP在纳米尺度空间的电磁场增强效应增加了光学梯度力,从而实现对纳米尺度样品的精确操纵,已逐渐成为一个非常重要的前沿研究方向。SPP超高的电磁场强度和纳米级别的空间尺寸使其在微弱信号增强、超分辨成像等方面拥有广泛的应用前景,表面增强拉曼光谱(SERS)技术即是利用金属纳米结构的电磁场局域能力和增强能力实现拉曼信号的增强。SPP光镊和SERS技术是两个具有共同研究基础的研究领域。在本文中,我们在详细介绍了表面等离激元基本原理的基础上,首先针对激光光镊目前存在的问题,展开了基于全光调控的聚焦型动态表面等离激元光镊技术,利用SPP光镊实现了对半导体纳米线在平面内的捕获与操控,实现了纳米线结构的搭建。其次,基于SPP近场能量增强效应展开了分子的SERS增强研究,将三种不同偏振对金属颗粒—金属膜型Gap结构增强效果在理论上进行比较,并在实验上进行了SERS光谱测量,揭示了此类型Gap结构的增强机理。本论文所涉及的主要研究内容如下:1.根据表面等离激元的发展背景,结合表面等离激元的应用以及本论文的主要研究内容,简要介绍了表面等离激元在光镊技术领域的研究现状和发展前景,并对SPP在拉曼增强领域的研究工作展开了初步介绍。2.系统介绍了表面等离激元和局域表面等离激元(LSP)的基本理论,分析了表面等离激元场与纳米结构作用力,并建立了纳米结构受力的理论模型。3.基于建立的纳米结构在SPP场中的受力模型,理论上分析了聚焦表面等离激元场对纳米线结构的作用力,并与传统光镊中的受力做了对比分析;搭建了基于线偏光紧聚焦激发表面等离激元场的光镊系统,进一步通过调控线偏振光的偏振方向以及激发SPP场的位置,实现了对氧化锌(ZnO)纳米线的动态和定向操控。4.基于紧聚焦激发的SPP场与金属纳米颗粒的LSP杂化耦合,可以在纳米结构与金属膜之间的Gap区域内产生纳米尺寸的局域增强电场,利用该Gap结构可以进一步实现对拉曼信号的增强;研究了不同偏振光束在Gap结构中所激发SPP耦合场的场局域与增强能力,并实验验证了该结构对分子SERS信号的影响。
[Abstract]:Surface Plasmon Polaritonne (SPP) is a coupling of free electrons and incident photons on a metal surface. The surface electromagnetic resonance mode produced by collective oscillations. Due to the characteristics of surface electric field localization and enhancement, SPP is manipulated in SPP optical tweezers and enhanced Raman scattering on the surface. Remarkable results have been obtained in the fields of SPP nanocrystalline etching and superresolution microimaging. The electromagnetic field enhancement effect of SPP in nanoscale space increases the optical gradient force and realizes the accurate manipulation of nanoscale samples. SPP has gradually become a very important frontier research direction. SPP has been widely used in weak signal enhancement and super-resolution imaging due to its ultra-high magnetic field intensity and nanoscale space size. Surface enhanced Raman spectroscopy (SERS). The technology is to utilize the electromagnetic field local ability and enhancement ability of metal nanostructure to realize the enhancement of Raman signal. SPP optical tweezers and SERS technology are two research fields which have common research foundation. On the basis of the detailed introduction of the basic principle of the surface isopitons, we first develop the focused dynamic surface isobaric optical tweezers technology based on all-optical regulation, aiming at the existing problems of laser optical tweezers. SPP optical tweezers are used to capture and manipulate semiconductor nanowires in the plane, and the structure of nanowires is constructed. Based on the near field energy enhancement effect of SPP, the SERS enhancement of molecules was studied. The enhancement effects of three different polarizations on the structure of metal particle metal film Gap were compared theoretically. The enhancement mechanism of this type of Gap structure is revealed by SERS spectroscopy. The main research contents in this thesis are as follows: 1. According to the development background of surface isoexcitators. Combined with the application of surface isophosphors and the main research contents of this thesis, the research status and development prospects of surface isophosphors in optical tweezers are briefly introduced. The basic theories of surface and local surface isophosphors are introduced. 2. In this paper, the interaction force between the surface isoexcitator field and the nanostructure is analyzed, and the theoretical model of the nanostructure force is established. 3. Based on the established model of the nanostructure force in the SPP field. The forces acting on nanowire structures by the focusing surface isoexcitator field are theoretically analyzed and compared with those in conventional optical tweezers. An optical tweezers system based on linearly polarized light compact focusing excitation surface isophosphor field is built to further regulate the polarization direction of linear polarized light and the position of excitation SPP field. The dynamic and directional manipulation of ZnO nanowires is realized. 4. The LSP hybrid coupling of metal nanoparticles and SPP field based on compact focusing excitation is achieved. The local enhanced electric field of nanometer size can be generated in the Gap region between the nanostructure and the metal film, and the Raman signal can be further enhanced by using the Gap structure. The field localization and enhancement ability of SPP coupling field excited by different polarized light beams in Gap structure are studied and the effect of the structure on the molecular SERS signal is verified experimentally.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O485;TB383.1

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