【作者】 何超；

【导师】 解宜原；

【作者基本信息】 西南大学 ， 信号与信息处理， 2017， 硕士

【摘要】 表面等离子体激元是一种沿着金属-介质界面传播的电磁表面波,由于其表面增强和高度局域的特性,使得人们得以克服衍射极限,在亚波长尺度的金属微结构中实现对光的传导和操控。目前,表面等离子体激元的理论研究趋于成熟,逐渐形成完善的学科,并在集成光学领域占有关键的一席之地。基于表面等离子体激元的应用研究也已在多个领域取得突破进展,包括集成波导、生物传感检测、纳米光刻、数据存储和新型光源等,从而极大地提升了光子器件的性能和光学回路的集成度。本文旨在帮助推进纳米尺度下光波的操控和光子器件设计,因此,基于表面等离子体激元在集成波导方面的研究,我们提出一类新型的滤波器和解复用器。本论文主要的研究内容如下:首先,根据金属的Drude模型,基于麦克斯韦方程组,理论分析了表面等离子体激元的色散特性,并介绍了表面等离子体激元的四个特征参数,以及根据波矢匹配在金属表面将表面等离子体激元激发出来的方法。接着,介绍金属-绝缘体-金属(Metal-Insulator-Metal,MIM)波导结构的原理和性质。其次,简要分析了本论文用到的研究方法,介绍了时域有限差分方法(Finite-Different Time-Domain,FDTD)的实现原理、激励源设定、稳定性要求和边界条件等,并结合FDTD仿真软件,对边耦合和肩耦合这两种谐振腔结构的耦合模理论做了阐述,分析验证了它们的传输和反射特性。然后,基于交叉形MIM波导的传输特性,我们将其与一组六边形谐振腔耦合,设计出一种新型的滤波器结构。该结构中,两条MIM波导相互正交,构成一个输入端口和三个输出信道。耦合模理论分析显示,通过调整不同信道间的表面等离子体波之间的相位,可以使得滤波信道中的传输效率达到峰值。而这一过程可以直接通过调节谐振腔的位置来容易地实现。我们采用FDTD仿真对理论分析进行了验证,此外,仿真显示在该结构中,通过调节耦合距离可以优化传输效率和线宽,还可以调节腔体的边长和填充介质来实现工作波长的调谐。最后,基于交叉波导上滤波器的理论研究,我们设计出一种新型的解波分复用器。该结构由一组十字交叉波导与三组六边形谐振腔构成,通过合理的布局,在三个信道中可以得到较为均衡的传输光谱,并最终得到较理想的传输效率和传输线宽,这说明该结构能成功实现波导交叉中的三端口解复用,对于构建复杂的光学系统和网络具有极大的应用潜力。更多还原

【Abstract】 The surface plasmon polaritons(SPPs)is a kind of waves propagating along the interface of the metal and dielectric.Due to their unique properties such as surface enhancement and high localization,they are allowed to conquer the diffraction limit and guide light waves on metal structure below the subwavelength.At present,theoretical studies on SPPs have gradually formed a significant subject and occupied an important place in the field of integrated optics.The applications based on SPPs have also made breakthroughs in a number of areas,including integrated waveguide,biosensor detection,nano-lithography,data storage and new light source,which greatly promote the performance of photonic devices and integration of optics circuits.This dissertation aimed to promote the manipulation of light waves and design of photonic devices in nanoscale.Therefore,based on the researches of SPPs on the integrated waveguide,we have proposed a novel filter and demultiplexer.The main contents of this dissertation are as follows:Firstly,based on the Drude model of metal and the Maxwell equations,we analyzed the dispersion characteristics of SPPs,and introduced the four characteristic parameters of SPPs.Besides,we described the means to stimulate SPPs on the metal surface employing the wave vector matching.Then,the principle and nature of metal-insulator-metal(MIM)waveguide were introduced.Secondly,we briefly analyzed the research models used in this dissertation.We introduced the basic principle of Finite-Different Time-Domain method(FDTD)firstly.In addition,the excitation source,the stability requirement and the boundary condition of FDTD simulation were mentioned.Next,in combination with FDTD simulation software,the coupled mode theory of the resonantors were described,and their transmission and reflection characteristics were demonstrated.Thirdly,based on the transmission characteristics of the MIM waveguide crossing,we have designed a novel filtering structure by coupling the crossing with a set of hexagonal resonators.In this structure,two MIM waveguides were orthogonal to each other to form an input port and three output channels.Coupled mode theory analysis showed that by tuning the phase between the SPP waves of different channels,the transmission efficiency in the filtered channel can reach the peak.And this process can be easily achieved by adjusting the position of the resonators.Next,the theoretical analysis was verified by FDTD simulation.In addition,the simulation showed that in this structure,the transmission efficiency and linewidth can be optimized by changing the coupling distance.Moreover,the working wavelength can be tuned by adjusting the length of resonators and the filling medium.Finally,based on the theoretical study of the filter,we have designed a novel demultiplexer.The demultiplexer was composed of a waveguide crossing and three sets of hexagonal resonators.Through reasonable layout,different wavelengths can be separated to three channels,and finally the impressive transmission efficiency and linewidth were obtained.It showed that the structure can be successfully implemented to demultiplexing in waveguide intersections.The proposed plasmonic demultiplexer may have significance for constructing complex waveguide networks and highly integrated optical communication systems.更多还原