金孔阵列-电介质与金-电介质孔阵列的强透射特性

Extraordinary Transmission Properties of Gold Aperture Array-Dielectric and Gold-Dielectric Aperture Array

采用时域有限差分(FDTD)法研究了金膜厚度、电介质折射率及其厚度对金孔阵列-电介质与金-电介质孔阵列两种结构强透射特性的影响。研究发现这两种结构都具有较好的强透射特性,这表明光与金膜表面自由电子的电荷密度波耦合成表面等离子激元(SPP),对增强透射起到了关键作用。金膜厚度是影响强透射特性的主要因素,其衰减长度为35nm;而与金膜相邻的电介质膜厚度对强透射特性影响极小。电介质折射率大小对强透射特性影响明显,折射率为1.8时能够获得较好的强透射特性。

The effects of gold film thickness, refractive index of dielectric and its thickness on extraordinary transmission properties of gold aperture array-dielectric and gold-dielectric aperture array are studied using the finitedifference time-domain （FDTD） method. The results show that both structures have a good extraordinary transmission property, which suggests that surface plasmon polariton （SPP）, formed by coupling of light and free electron charge density wave of gold film surface, plays a key role in enhanced transmission. The gold film thickness is the major factor affecting the extraordinary transmission property, and its decay length is 35 nm; the thickness of dielectric film adjacent to the gold film has minimal impact on the extraordinary transmission property. The refractive index of dielectric has a distinct impact on the extraordinary transmission property, and the refractive index of 1.8 may lead to a good extraordinary transmission property.