基于塔姆激元-表面等离极化激元混合模式的单缝加凹槽纳米结构的增强透射  

Enhanced optical transmission by exciting hybrid states of Tamm and surface plasmon polaritons in single slit with multi-pair groove nanostructure

作　　者：祁云平 周培阳 张雪伟 严春满 王向贤[2] Qi Yun-ping1, Zhou Pei-Yang1, Zhang Xue-Wei1, Yan Chun-Man1, Wang Xiang-Xian2(1Engineering Research Center of Gansu Province for Intelligent Information Technology and Application, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China;2School of Science, Lanzhou University of Technology, Lanzhou 730050, Chin)

机构地区：[1]西北师范大学物理与电子工程学院甘肃省智能信息技术与应用工程研究中心,兰州730070 [2]兰州理工大学理学院,兰州730050

出　　处：《物理学报》2018年第10期179-186,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61367005;61741119);甘肃省自然科学基金-创新基地和人才计划(批准号:17JR5RA078)资助的课题~~

摘　　要：金属单缝纳米结构因为结构简单、易于集成,常用在基于表面等离极化激元(surface plasmon polaritons,SPPs)的纳米结构中构建光源.但是,金属亚波长单缝结构一直存在透射率低的问题,如何提高其透射率一直是研究的重点.为了更好地提高金属亚波长单缝的透射率,本文对之前文献提出的分布式布拉格反射镜(distributed bragg reflector,DBR)和金属银薄膜纳米缝结构进行改进,在金属银薄膜两侧设计凹槽.当TM偏振光由DBR侧入射至DBR-银纳米缝结构时,DBR-银膜界面上和银膜入射侧凹槽一起激发的塔姆激元(Tamm plasmon polaritons,TPPs)和SPPs,以及纳米缝和银膜出射侧凹槽对的SPPs同时激发,利用凹槽激发的SPPs和银膜表面处的TPPs-SPPs混合模式的干涉相长耦合作用,通过塔姆激元的局域场增强效应和两侧凹槽与单纳米缝的干涉相长耦合作用进一步提高了表面等离极化激元模式的激发效率,再加上纳米缝中的类法布里-珀罗腔共振效应,使纳米缝的透射率得到增强.本文采用有限元方法研究了DBR-银纳米缝结构上单纳米缝加凹槽的透射特性.经过一系列参数优化,使DBR-银纳米缝凹槽结构的最大透射率增加到0.22,相对于TiO_2-银纳米缝结构的透射率(0.01)提高了22倍,比文献[23]得到的最大透射率0.166有所提高.研究结果在纳米光源设计、光子集成电路和光学信号传输等相关领域具有一定的应用价值.In recent years, a metallic single slit nanostructure or slit array structure, due to simple structure and easy-to integration, has been used to construct a light source in the nanostructures based on the surface plasmon polaritons（SPPs）. However, the problem of low transmission through an isolated subwavelength single slit nanostructure is still existent. The main reason is that the excitation efficiency of SPPs in the single slit nanostructure is not too high.Therefore, how to effectively enhance the optical transmission has become a research focus. In order to further improve the transmittance of the metallic single slit nanostructure, in this paper, we improve the single slit nanostructure imbedded in the metal silver thin film on a distributed Bragg reflector（DBR） proposed in previous literature. As a result, a novel method of designing a single slit on a DBR is proposed to effectively enhance the optical transmission in a single slit by improving the excitation efficiency of SPPs. Our proposed novel structure is made up of a subwavelength single nano-slit surrounded symmetrically by a pair of grooves on both sides of metal silver film on a distributed Bragg reflector. When the TM polarized light is illuminated from the DBR side of our proposed structure to the DBR-silver slit-grooves nanostructure, the Tamm plasmon polaritons（TPPs） at the interface between the silver film and the DBR and the SPPs in the slit on the entrance side of the silver film are excited at the DBR-silver film interface, and the SPPs in the slit and grooves pair on the exit side of the silver film are excited simultaneously. In our proposed structure, coupling between the TPPs and the SPPs leads to the hybrid state of Tamm and surface plasmon polaritons in the slit and grooves. Finally, taking advantage of constructive interference between SPPs excited by the grooves and exciting hybrid states of TPPs-SPPs in the slit, due to the local field enhancement effect of the TPPs mode and the coupling effect of constructive interfe

关 键 词：光学异常透射 塔姆激元 表面等离极化激元 类法布里-珀罗腔共振 

分 类 号：TG111[金属学及工艺—物理冶金]