亚波长金属椭球周期阵列—金属薄膜复合结构的光透明特性研究

Investigation of Optical Transparent Properties of Sub-Wavelength Complex Structure of a Metal Ellipsoid Periodic Array and a Metal Film

设计了一种新型的亚波长透明金属结构,该结构由一层六角晶格排列的椭球形金纳米颗粒沉积在金膜上构成。使用时域有限差分法计算了该结构的透射特性,发现该金属结构具有强的光学透明现象。随着椭球纵横比或金膜厚度的增加,共振透射峰出现明显的蓝移,且透射率发生显著变化。此外还发现,金纳米椭球颗粒阵列位于金膜上表面时的透射率比位于下表面时的透射率要大。

A novel sub-wavelength transparent metal structure consisting of with a layer of gold ellipsoid nanoparticles arranged into the hexagonal lattice on the surface of a gold film is proposed. The transmission characteristics of the structure are investigated by using the finite-difference time-domain （FDTD） method. Simulation results show that the structure presents pronounced optical transparent behaviors. With the increase of the ellipsoid aspect ratio or the gold film thickness, obvious blue shift of the narrow resonant peak appears, accompanied by the pronounced change in transmittance. The transmission spectrum with much narrower peak is achieved in the proposed structure as compared to that of the structure with a gold nanosphere array on the thin gold film. In addition, we also find that the transmittance of the structure with the gold ellipsoid array on the top surface of the gold film is larger than that with the gold ellipsoid array on the bottom surface of the gold film.