渔网电磁超介质左手通带的超常透射及其电场增强效应的数值研究

Numerical Studies of Left-Handed Passband with Extraordinary Optical Transmission and Field Enhancement in Fishnet Metamaterials

本文利用电磁场数值模拟方法研究了分布矩形孔阵列的"金属-电介质-金属"三明治渔网电磁超介质在其左手通带发生的超常透射现象和不同模式激发下的电场增强效应。结果证实左手通带紧邻的超常光学传输峰源于波导共振模式,利用超常传输效应可以有效降低电磁超介质的损耗,提高左手性能;波导共振模和左手通带对应的反对称磁模能够分别在孔洞和金属夹层区域激发超过11倍的增强电场,因此渔网电磁超介质结构在表面增强光谱和传感等方面也具有潜在应用价值。

We investigated numerically the left-handed behavior occurring together with the extraordinary optical transmission（EOT）and the corresponding electric field enhancement by exciting different modes in a fishnet metamaterial,＂metal/dielectric/metal＂ sandwich structure perforated by an array of rectangular holes.It is demonstrated that the EOT peak adjacent to the left-handed band stems from a waveguide resonant mode and the effect of the EOT helps to reduce the losses and improve the left-handed performance.The calculations also show that more than 11-fold enhancement of the electric field can be achieved within the holes and between the two metal plates by exciting respectively the waveguide resonant mode and the magnetic mode associated with left-hand behavior,suggesting the possible applications of the fishnet metamaterials in surface enhanced spectroscopy and sensors.