中文摘要：

单纳米金属缝结构,由于其结构紧凑、易于集成、耦合效率高,常常在基于表面等离子体激元（surface plasmon polaritons,SPPs）的纳米结构器件中用于构建光源.但是,单纳米缝的低透射率一直是该结构向实际应用转化中的问题;实际上,如何有效地增强其透射率一直是研究的重点.本文提出了一种有效增强单纳米缝异常透射的方法和结构,该结构由分布式布拉格反射镜（distributed bragg reflector,DBR）和金属银薄膜纳米缝构成.当TM偏振光由DBR侧入射至DBR-银纳米缝结构时,DBR-银膜界面上的塔姆激元（Tamm plasmon polaritons,TPPs）和纳米缝中的SPPs能够同时被有效激发,并相互耦合形成TPPs-SPPs混合模式,当TPPs与SPPs满足波矢匹配条件时,利用TPPs的局域场增强效应可显著提高SPPs的激发效率,结合纳米缝中的类法布里-珀罗腔共振效应,最终可实现对单纳米缝异常透射率的有效增强.本文利用传输矩阵法和有限元算法分析了DBR-银纳米缝结构上单纳米缝的透射特性.经过参数优化,在银膜厚度为100 nm、纳米缝宽为11 nm时,DBR-银纳米缝结构的最大透射率为0.166,相对于TiO_2银纳米缝结构（无DBR）的透射率（0.01）,提高了16倍.该研究从基本物理机理出发,实现了对单纳米缝异常透射的增强,研究结果在纳米光子学、近场光学成像与探测、极化激元激光器等相关领域具有潜在的应用价值.

英文摘要：

Extraordinary optical transmission（EOT） through a metallic nano-slit or nano-slit arrays has become an efficient method to manipulate the light on a subwavelength scale. While a variety of nano-devices based on surface plasmon polaritons（SPPs） could be an ideal candidate for the next-generation ultra-compact integrated photonic circuits, this EOT phenomenon is also generally attributed to the excitation of SPPs in the nano-slit. Thus, due to its being compact in structure and amenable to integrate with other nano-devices, single nano-slit can be implemented to construct an optical source in the nano-device based on SPPs. However, the transmission through an isolated nano-slit is too low to be practically used. The main reason is that the excitation efficiency of SPPs in the nano-slit is not high enough. In fact,one of the key issues is how to enhance the excitation efficiency in a nano-slit. In this paper, a novel method and the related structure are proposed to effectively enhance the EOT in a single nano-slit by improving the excitation efficiency of SPPs. This structure is made up of a silver film on a distributed Bragg reflector（DBR）, where a single nano-slit is imbedded in the silver film. Under the illumination of a TM polarized light from the DBR side of this structure, the Tamm plasmon polaritons（TPPs） at the interface between the silver film and the DBR and the SPPs in the nano-slit can be excited simultaneously. The TPP is another surface mode, which describes how an electromagnetic field is localized at the boundary of silver film and the DBR. In this structure, coupling between the TPPs and the SPPs leads to the appearance of a TPP-SPP hybrid state. When the wave-vectors between the TPP and the SPP modes are matched,due to the local field enhancement of the TPP mode, the excitation efficiency of SPPs can be improved significantly.Furthermore, utilizing the quasi Fabry-Pérot（F-P） resonance in the nano-slit, where a single nano-slit can be regarded as an F-P cavity with two open end