亚波长金属光栅的表面等离子体激元共振特性

Resonant properties of sub-wavelength metallic gratings

亚波长金属光栅在共振波长处有光场局域增强、异常透射等现象,为深入认识其共振机制,本文研究了亚波长金属光栅的表面等离子体激元(SPP)共振特性。通过研究不同金属光栅的几何结构以及金属介电常数对SPP共振波长的影响,获得了3种共振波长的基本物理机制。采用周期边界元法进行数值模拟,在边界积分方程的基础上结合平面波展开方法来处理任意形状的周期性结构。模拟结果表明,3种共振波长可以分别由金属的材料、金属光栅周期和金属光栅厚度所调谐。该研究为微纳米光学器件的设计提供了依据。

Sub-wavelength metallic gratings have extraordinary transmission efficiency and local field enhancement in resonant wavelengths.In order to deeply understand the resonant discipline,the resonant origins of the sub-wavelength metallic gratings were investigated.Three resonant wavelengths were analyzed by adjusting the geometric parameters and materials of the gratings,and the physical disciplines of three different resonant wavelengths were obtained.In the simulation,the periodical boundary method based on the boundary integral equation combined with a plane wave expansion method was used to process the period structures with arbitrary shapes.The numerical results show that three resonant center wavelengths can be tuned by the materials,periods,and the thicknesses of the gratings.It is believed that this study will provide useful information for further designing micro-nano optical elements.