周期性磁等离激元纳米结构的光学和磁光特性研究

发布时间：2018-01-06 21:22

本文关键词：周期性磁等离激元纳米结构的光学和磁光特性研究　出处：《南京大学》2017年博士论文　论文类型：学位论文

【摘要】：同时具有磁光特性和等离激元特性的磁等离激元纳米结构已成为近几年研究的热门课题。由于磁等离激元纳米结构充分地有效结合了表面等离激元和磁性两种特性,使光波在具有表面等离激元共振现象的纳米结构内部诱导的电磁场显著增强,从而大大增强了磁光效应。同时,该结构可以通过外加磁场来对等离激元共振进行有效控制。因此,磁等离激元纳米结构的研究促进了许多新型器件的快速发展,例如,生物、化学传感器,磁光数据存储,光学隔离器、调节器,以及通讯行业中的集成光子器件等等。尽管人们在磁等离激元纳米结构中为了同时获得优良的磁光特性和光学特性方面做过大量的研究,然而,如何设计同时具有良好表面等离激元和磁光特性,并且可以进行有效调控的磁等离激元系统,仍然是一个充满挑战的课题。本论文中,我们首先成功发展了时域有限差分方法,使其能够解决包含有磁性材料纳米结构的光学和磁光效应问题。合理构建了一维、二维周期性磁等离激元晶体结构,利用扩展时域有限差分方法系统研究了所构建的磁等离激元晶体结构的光学和磁光特性。通过系统优化晶体结构的几何参数,我们在可见光和近红外波段均同时得到了较高的透射率和较大的磁光法拉第旋转角,同时对其物理机制进行了详细地诠释。为了验证理论研究的正确性和可靠性,我们在实验方面利用激光干涉光刻技术和磁控溅射技术制备了磁等离激元纳米结构,研究了不同体系的光学和磁光特性,探讨了表面等离激元与磁光效应增强的内在联系。本文的具体研究工作主要包括以下三个方面:1.构建了一种由双层贵金属光栅和磁性透明介质组成的磁等离激元晶体结构,利用扩展时域有限差分方法对其光学特性和磁光特性进行了深入系统的研究。通过系统优化双层金属光栅结构的结构参数,我们在两个波段处均得到法拉第旋转角共振增强,并且其符号产生了反转,在另外一个透射率频谱区域得到了 57%的异常光透射的同时获得了 44倍增强的法拉第旋转角。文中详细讨论了入射角、结构中双金属光栅之间台柱介质的折射率以及结构周期对磁等离激元晶体结构的光学和磁光特性的影响。研究表明,我们可以通过简单调整双金属光栅构成的磁等离激元晶体结构的几何参数,诸如,折射率、周期等,以及入射角度大小来调控该结构的光学和磁光特性。另外,我们还研究了单层贵金属光栅与磁性介质构成的磁等离激元晶体结构的光学和磁光特性,并与双层金属光栅结构的光学和磁光特性进行了比较。通过两者的对比,我们发现双层金属光栅结构的光学特性和磁光特性均优于单层金属光栅结构的光学和磁光特性。此外,我们对透射率谱中共振波峰、波谷和法拉第旋转角增强、符号发生反转以及双层金属光栅结构的光学和磁光特性优于单层金属光栅结构的光学和磁光特性的物理机制进行了深入地讨论、解释。研究表明,透射共振波峰和波谷的出现主要依赖于表面等离激元共振和波导模式的激发及两者的相互耦合;法拉第旋转角的增大是由磁性介质中两类波导模式—TM模式和TE模式相互转化的转化效率及光波在磁性介质层中传播的有效距离所决定的。2.研究了二维周期性由被蘑菇状金属帽子遮挡的圆孔和环孔系列构成的磁等离激元晶体结构的异常光透射和增强的法拉第磁光效应现象。通过系统优化磁等离激元晶体结构的几何参数,我们在两种不同晶体结构中的透射率谱和法拉第磁光效应谱的可见光和近红外波段均同时得到了较大的法拉第旋转角和较高的透射率。同时,我们对透射率谱中的共振波峰和磁光效应谱中法拉第旋转角增强等产生的物理机理借助于透射共振位置处的电场、磁场的空间分布等手段进行了详细地阐述。研究结果表明,透射共振波峰的出现主要取决于LSPR模式、SPP模式和波导模式的激发及它们之间的相互耦合作用;法拉第旋转角的增大是由磁性介质中两类波导模式—TM模式和TE模式相互转化的转化效率及光波在磁性介质层中传播的有效距离所决定的。3.从实验方面研究了一维周期性磁等离激元纳米结构的光学和磁光横克尔特性。首先从理论上详细阐述了磁光横克尔效应产生以及表面等离极化激元对其显著增强的内在机理。然后,利用激光干涉技术制备了光刻样品以及磁控溅射技术制备了多层金属/氧化物介质薄膜样品,从实验上研究了样品在不同情况下的反射率和磁光横克尔值随入射角变化关系,详细讨论了非磁性氧化物介质层的引入对磁等离激元纳米结构的光学和磁光特性的影响,并从理论上给予了合理的解释。同时,本部分的实验结果验证了前面理论的正确性和可靠性。
[Abstract]:At the same time with the optical and magnetic properties and magnetic properties of plasmonic plasmonic nanostructures has become a hot topic of research in recent years. Due to the magnetic plasmonic nanostructures fully combines surface plasmon and magnetic properties of two kinds of electromagnetic field, the light wave induced within nano structures with surface etc. plasmon resonance phenomenon increased significantly, thereby greatly enhancing the magneto-optical effect. At the same time, the structure can be obtained by applying an external magnetic field on the plasmonic resonances were effectively controlled. Therefore, the study of magnetic polaritons nano structure and promote the rapid development of many new devices, such as biological, chemical sensors. Magneto optical data storage, optical isolator, regulator, and communications industry in integrated photonic devices and so on. Although people in the magnetic plasmon nano structure in order to obtain magneto-optical properties and excellent optical properties do A large number of researches, however, how to design a good surface plasmon and magneto optical properties, and can effectively control the magnetic plasmon system is still a challenging task. In this thesis, we first developed a finite difference time domain method, which can solve contains optical and magneto-optical effect magnetic nanostructured materials. The reasonable construction of one-dimensional, two-dimensional periodic magnetic plasmon crystal structure, using the extended finite difference time domain of the magnetic plasmon crystal structure optical and magneto-optical properties of system. Through the geometric parameter optimization of crystal the structure, we in the visible and near infrared bands were also obtained higher transmittance and larger magneto optical Faraday rotation angle, and the physical mechanism of a detailed interpretation. In order to verify the correctness of theoretical research And reliability, we use the laser in the experiment of magnetic plasmonic nanostructures prepared by interferometric lithography and magnetron sputtering technology, the optical and magneto-optical properties of different systems, this paper discusses the intrinsic relations between surface plasmon and magneto-optical effect enhancement. The main research work in this paper includes the following three 1.: construction which is composed of double noble metal grating and transparent magnetic medium magnetic plasmon crystal structure, using the extended FDTD method is studied on its optical properties and magneto optical properties. Through the system to optimize the structure parameters of double-layer metallic grating structure, we in two the wavelength can be enhanced Faraday rotation resonance, and produced a reversal of its symbol, in another area of transmission spectrum to get 57% abnormal light transmission and gain enhancement of 44 times Fala The rotation angle is discussed in detail. The incident angle, a medium between the double effect of metal grating in refractive index and periodic structure optical and magneto-optical properties of magnetic crystal structure from the. Research shows that we can form through the simple adjustment of double metal grating from the magnetic parameters, excitation the crystal structure such as refractive index, cycle regulation, optical and magneto-optical properties of the structure and size of the incident angle. In addition, we also studied a single layer of precious metal grating and magnetic media such as magnetic optical and magneto-optical properties from the crystal structure, and compared with the optical and magneto-optical properties double layer metal grating structure. Through the comparison, we found that the double metal grating and optical properties of optical and magnetic properties are better than that of single metal grating structure, optical and magneto-optical properties. In addition, we on the transmission rate In the spectrum of resonance peaks and troughs and the Faraday rotation angle increases, the physical mechanism of symbol reversed and double metal grating optical and magneto-optical properties are better than that of single metal grating and optical and magneto-optical properties were deeply discussed and explained. Research shows that the coupling between the transmission resonance peaks and troughs occur mainly depends on the excitation and both in surface plasmon resonance and waveguide mode; increase the Faraday rotation angle is determined by the effective distance of two kinds of magnetic medium waveguide mode conversion efficiency and light transformation between TM mode and TE mode in the magnetic medium layer spread by.2. were studied by two-dimensional periodic metal mushroom hat blocked hole and ring hole series constitute the magnetic plasmon crystal structure of abnormal light transmission and enhancement of the Faraday magneto-optical effect phenomenon. By optimizing the system of magnetic plasmon The geometric parameters of element of crystal structure, we in the two different crystal structure in the transmittance spectrum and Faraday magneto-optical effect spectrum of visible light and near infrared transmittance were obtained at the same time large Faraday rotation angle and higher. At the same time, we have to peak in the spectrum of resonance wave transmittance spectra and magnetic optical effect of Faraday rotation corner enhancement electric field generated by the physical mechanism of the transmission resonance position, the spatial distribution of magnetic field and other means are discussed in detail. The results show that the transmission resonance peak appears mainly depends on the interaction between the LSPR mode, SPP mode and waveguide mode excitation and the Faraday rotation angle is increased; determined by the effective distance of two magnetic medium waveguide mode conversion efficiency and light transformation between TM mode and TE mode in the magnetic medium layer spread the.3. from the experiment The research of one-dimensional periodic magnetic plasmon optical and magneto-optical properties of transverse Kerr polaritons nano structure. Firstly, theoretically elaborated and surface magneto optic Kerr effect of transverse plasmon polarization on the enhanced mechanism. Then, lithography samples and magnetron sputtering technology of multilayer metal / oxide dielectric thin film samples were prepared by using laser interferometry system, from the experiment of the samples under different conditions of reflectivity and magneto optical cross Kerr values change with the incident angle, the introduction of non magnetic oxide dielectric layer of optical and magneto-optical properties of magnetic polaritons nano structure is discussed in detail, and from the theory of giving reasonable explanation. At the same time, this part of the experiment results verify the correctness and reliability of the previous theory.

【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1

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