内置金属/电介质同心圆柱的金属孔阵列结构强透射特性

Extraordinary Transmission Property of Metallic Hole Array with a Built-in Metal/Dielectric Concentric Cylinder

采用有限时域差分(FDTD)法研究了内置金属/电介质同心圆柱结构的材料属性、半径及其相对高度对金属孔阵列强透射特性的影响。发现该结构与内置单一金属、单一电介质和电介质/金属三种不同的同心圆柱结构相比较,光的透射性能得到显著的增强;这种内置金属/电介质同心圆柱结构具有进一步增强表面等离激元与局域表面等离激元共振耦合作用。结果表明,金属、电介质的材料属性对强透射特性影响明显,当金属圆柱为Au、电介质圆柱折射率较小时,其透射性能较好;圆柱半径是影响透射率与共振峰位置的主要因素,半径越大,共振峰红移越明显,但其透射率先增大而后持续减小。同时,金属/电介质圆柱的相对高度也影响透射率大小,当金属圆柱高度为60nm时,其透射性能较好。

In this paper,the effects of material,radius and relative height of a built-in metal/dielectric concentric cylinder on extraordinary transmission properties of metallic hole array were investigated with the finite-difference time-domain（FDTD）method.It is found that the structure,compared to the structure with built-in single metal concentric cylinder,single medium concentric cylinder or dielectric/metal concentric cylinder, shows a good extraordinary transmission property.This suggests that resonance effect of surface plasmon polariton and localized surface plasmon are further enhanced by the built-in metal/dielectric concentric cylinder.It shows the material of metal and dielectric has a distinct impact on the extraordinary transmission property. When the metal cylinder material is Au and the refractive index of the dielectric cylinder is relatively small, the transmission performance is better.The radius is the major factor affecting the transmittance and the position of the resonance peak. The radius is larger,the resonance peak redshifts more obviously,but the transmittance firstly increases and then decreases steadily.At the same time,relative height of the metal/dielectric cylinder also influences the transmission,and the transmission performance is better when the height of the metal cylinder is 60 nm.