二维亚波长金属小孔阵列的透射光增强效应

Optical transmission enhancement of two-dimensional subwavelength hole arrays in metallic films

对金属薄膜上的二维亚波长小孔阵列的光透射增强现象进行了数值模拟 ,结果显示不仅实际金属薄膜上的小孔阵列结构具有透射增强效应 ,理想导体薄膜的相同结构也具有透射增强效应 ,但没有实际金属薄膜的增强明显 .通过分析指出 ,这种小孔阵列的光透射增强效应是一种复杂的波导耦合效应 .与金属薄膜上的表面电流一样 ,表面等离激元波具有将入射光能量从金属表面向小孔转移的作用 ,但不是透射增强的本质原因 .

Numerical simulation has been performed on the optical transmission enhancement of a metallic film with a two-dimensional subwavelength hole array. The results show that the ideal conducting film of the same array structure also presents a transmission enhancement, but the enhancement is not higher than that of the real one. Further analysis reveals that a complicated waveguide coupling effect is responsible for the enhanced transmission. The excitation of surface current on metallic surface transfers the light energy of incidence from metallic surfaces to the holes and then adjusts the optical transmission. We believe that the resonant excitation of surface plasmon is not necessary for the enhancement effect.