基于金属和介质纳米颗粒的光频天线的研究

发布时间：2018-03-23 05:35

本文选题：基于　切入点：金属　出处：《南京大学》2014年硕士论文　论文类型：学位论文

【摘要】：传统天线是连接无线电系统和外部世界的枢纽,其工作频段覆盖整个无线电波,被广泛应用于通讯、探测等众多领域,成为人们生活重要的组成部分。近年来微加工技术飞速发展,人们期望研制能够工作在光频波段的天线系统,并且期望利用光频天线在亚波长尺度下对光场进行操控。最新的研究结果表明,光频天线在光电转换、光学传感探测、荧光增强、生物检测等领域有着诱人的应用前景。本论文从理论和实验两方面研究基于金属和介质纳米颗粒的光频天线,我们首先探讨了金属纳米天线系统中局域等离激元的激发和再辐射效应,给出了纳米结构的形状因子对天线辐射效率的影响；为了避免金属在光频波段的本征损耗,我们进而研究介质纳米颗粒系统的光学性质,揭示其独特的辐射机制,构造出较高效率的宽带光频天线。具体包括以下两部分内容：第一,我们研究了基于金属纳米颗粒的等离激元光频天线的辐射机制。在理论上,我们利用时域有限元差分方法证实：当光波照射到金属纳米颗粒时,金属颗粒的表面激发出局域型表面等离激元,这些局域表面等离激元诱导电偶极子进而发生偶极辐射。在此基础上,我们系统考察了纳米结构中局域等离激元的共振效应与纳米结构单元的大小和形状的关系,计算出几种纳米结构的散射截面和辐射效率；实验上我们利用电子束曝光的方法制备了几种等离激元光频天线样品,并利用微区光谱仪和分光光度计测量样品透射谱与散射谱,实验观测与数值模拟结果基本吻合,证实了该系统中局域表面等离激元的激发和再辐射效应。此外,我们还讨论了进一步优化等离激元光频天线的设计和实验表征。第二,我们研究了基于介质纳米颗粒的光频天线及其辐射机制。利用时域有限元差分方法,我们证实了耦合硅纳米圆柱系统中宽带散射效应。首先,在单个硅纳米圆柱中,我们观察到明显的电共振和磁共振。通过将两个硅纳米圆柱相互靠近,我们构建了硅纳米圆柱二聚体,从而单个硅纳米圆柱的磁共振和电共振相互靠近,形成混合的共振模式；同时一个新的磁共振模式出现在长波长位置,表现出宽带散射效应,该效应来源于硅纳米圆柱间的磁相互作用。进一步地,在硅的三聚体中,宽带响应可以进一步增强。宽带散射通过散射谱得到证实,而磁相互作用通过空间场分布以及反推介电常数和磁导率得到证实。该理论研究为实现硅基宽带纳米天线和探测器提供了新的思路。综上所述,我们从理论和实验两方面研究了基于金属和介质纳米颗粒的光频天线,一方面揭示了金属纳米天线系统中局域等离激元的激发和再辐射效应,并且利用纳米结构的形状因子来提高等离激元天线辐射效率；另一方面揭示了介质纳米颗粒系统的光散射特征和其独特的辐射机制,构造出低损耗的宽带光频天线。研究工作为设计和制备亚波长光频天线提供了新思路,在光集成、光传感和探测以及高效率太阳能电池等方面具有潜在的应用前景。
[Abstract]:The traditional antenna is connected to a radio system and the outside world hub, its work band covering the entire radio waves, is widely used in many fields such as communication, detection, become an important part of people's life. In recent years, the rapid development of micro machining technology, antenna system is expected to develop a work in optical frequency band, and is expected to operate the light field in the subwavelength scale with optical antennas. The latest research results show that the optical frequency antenna in photoelectric conversion, optical sensing detection, fluorescence enhancement, field biological detection has an attractive application prospect. This paper from two aspects of theory and experiment of optical frequency antenna of dielectric and metal nanoparticles based on, we firstly investigated the localization of metal nano antenna system from the excited element and re radiation effects, given the influence of shape factor of nano structure on the antenna radiation efficiency ; in order to avoid the intrinsic loss of metal in optical frequency band, we further study the optical properties of dielectric nano particle system, reveals its unique radiation mechanism, construct the broadband optical frequency antenna with high efficiency. The specific contents include the following two parts: first, we study on the basis of metal nanoparticle plasmon light frequency antenna radiation mechanism. In theory, we use the finite difference time domain method confirmed: when the light irradiation to metal nanoparticles, surface metal particles excited out of domain type surface plasmon, the localized surface plasmon induced electric dipole and dipole radiation. Based on this, our system study the relationship between the local nano structure from the resonance effect and nano structure unit of polaritons in the size and shape of the cross section is calculated, and the radiation efficiency of several nanostructures; experiment on me Using the method of electron beam lithography prepared several plasmon optical frequency antenna samples, and the use of micro spectrometer and spectrophotometer to measure the transmission spectrum and scattering spectra of samples, experimental observation and numerical simulation results, proved that the system of localized surface plasmon and re radiation effects. In addition, we also discuss the design and experimental characterization to further optimize the plasmon optical frequency antenna. Second, we study the optical frequency and antenna radiation mechanism of dielectric nanoparticles based on using finite difference time domain method, we confirmed the wideband scattering coupling effect of silicon nano cylindrical system. First of all, in a single silicon nano cylinder, we observed the electric resonance and magnetic resonance obviously. By two silicon nano cylinder close to each other, we constructed two poly silicon nano cylindrical body, so a single silicon nano cylindrical magnetic resonance and Electric resonance close to each other, forming a resonance hybrid model; at the same time a new magnetic resonance mode in long wavelength position, exhibit broadband scattering effect, the effect comes from the silicon nano cylinder magnetic interaction. Further, the silicon trimer in response to further enhance broadband broadband scattering through. The scattering spectrum was confirmed, and the magnetic interactions through space distribution and promotion of anti permittivity and permeability are confirmed. The research provides a new method to realize broadband antenna and nano silicon detectors. In summary, we from two aspects of theoretical and experimental research of the optical frequency antenna of dielectric and metal nanoparticles based on a reveals the local metal nano antenna system from the excited element and re radiation effects, and the shape factor of nano structure to improve the radiation efficiency of plasmon polaritons antenna; On the other hand reveals the characteristics of light scattering medium nanoparticle systems and their unique radiation mechanism, construct the broadband optical frequency antenna and low loss. The research work provides a new way of sub wavelength optical frequency antenna is provided for the design and manufacture, in optical integration, has a potential application prospect of optical sensors and detection and high efficiency solar cell and so on.

【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN826;TB383.1

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