偏振方向及结构间耦合作用对空心方形银纳米结构表面等离子体共振的影响

空心方形纳米结构能够激发更大面积的增强电场,故其可以作为衬底用于表面增强拉曼散射.应用离散偶极子近似算法研究了空心方形银纳米结构的消光光谱及其近场电场分布与入射光偏振方向之间的关系.研究表明,空心方形银纳米结构的表面等离子体共振峰不随入射光偏振方向的改变而移动,但是其表面增强电场分布却强烈地依赖于入射光的偏振方向.另外,还讨论了空心方形银纳米结构间的耦合作用对其表面等离子体共振模式的影响.结果发现,可以通过调节结构间的距离来改变结构间的耦合作用,同时改变了表面等离子体共振峰的位置.这些结果将为理解闭合纳米关键词：空心方形银纳米结构表面等离子体偏振电场耦合

Effects of incident polarization and electric field coupling on the surface plasmon properties of square hollow Ag nanostructures

Square hollow nanostructure can induce a large-area enhanced electric field at the main plasmon peak. Therefore, it can be used as a substrate for the surface enhanced Raman scattering. The effects of the incident polarization on the extinction spectrum and the electric field distribution of the square Ag nanostructure are studied by the discrete dipole approximation method. The results show that the plasmon peaks do not shift with the variation of incident polarization. However, the electric field distribution is strongly dependent on the direction of incident polarization. Additionally, the effect of the electric field coupling between adjacent square Ag nanostructures on the plasmon mode is also studied. It is found that the plasmon resonance can be tuned by varying the separation between adjacent squares. These results could be used to guide the preparation of such closed nanostructures for specific plasmonic applications.