基于H形金属狭缝阵列结构双共振谷折射率传感特性

Refractive Index Sensing Property of Two Resonance Dips Based on H-Shaped Metal Slit Array Structure

摘要:

提出了一种基于H形金属狭缝阵列的新型结构。利用该结构形成的法布里-珀罗腔(Fabry-Perot,F-P)来加强表面等离激元的耦合作用,以获得一种双共振反射现象；同时研究了基于该现象的折射率传感特性。采用时域有限差分法研究了该结构中狭缝长度、宽度、金膜厚度等参数对双共振反射现象的影响。研究发现,双共振谷波长可由以上主要参数有效调控,当竖直狭缝长度为150nm、水平狭缝长度为200nm、狭缝宽度为50nm、金膜厚度为300nm时,该结构具有较好的双共振反射现象,其灵敏度分别为590和1199nm/RIU。该发现为新一代高性能表面等离子共振传感器设计提供了理论参考。

Abstract:

A novel structure based on H-shaped metal slits array is proposed in this paper. The Fabry-Perot cavity formed by the structure is used to strengthen the coupling effect of the surface plasmon polariton to obtain a phenomenon of two resonance reflections. And also the refractive index sensing characteristics based on this phenomenon were studied. The influence of length and width of slit and thickness of gold film on the two-resonance reflection was studied with the method of finite difference time domain. It is found that the wavelengths of the two resonance dips can be effectively controlled by the above parameters. When the length of the vertical slits is 150nm, the length of the horizontal slit is 200nm, the width of the slits is 50nm, and the thickness of the gold film is 300nm, the structure has a good phenomenon of two resonance reflections, and its sensitivity is 590 and 1199nm/RIU, respectively. The discovery can provide a theoretical reference for the design of a new generation of high-performance surface plasmon resonance sensors.