The need for an easy to fabricate perfect and narrowband light absorber in the visible range of electromagnetic (EM) spectrum has always been in demand for many scientific and device applications. Here, we propose a metal-dielectric-metal (MDM) 1-D grating plasmonic structure as a perfect narrow band light absorber in the visible and its application in glucose detection. The proposed structure consists of a 1- D grating of gold on the top of a dielectric layer on a gold film. Optimization for dielectric grating index (n), grating thickness (t), grating width (W), and grating period (P) has been done to improve the performance of plasmonic structure by calculating its quality factor and figure-of-merit (FOM). The optimized plasmonic structure behaves as a perfect narrowband light absorber. The flexibility to work at a specific wavelength is also offered by the proposed structure through an appropriate selection of the geometrical parameters and refractive index of the dielectric grating. The equivalent RC model is used to understand different components of the proposed structure on the optical response. The absorption response of the structure is invariant to the incident angle. Moreover, the calculated absorbance of the proposed plasmonic structure is ~ 100% with a narrow full-width half maxima (FWHM) of ~ 2.8 nm. We have numerically demonstrated a potential application of the proposed MDM absorber as a plasmonic glucose sensor in the visible range with detection sensitivity in the range of 140 to 195 nm/RIU.

中文翻译：

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一维金属-介电金属光栅结构作为可见光中的超窄带完美等离子体吸收剂及其在葡萄糖检测中的应用

在许多科学和设备应用中，一直需要在电磁（EM）光谱的可见光范围内易于制造完美的窄带光吸收器。在这里，我们提出一种金属-电介质-金属（MDM）一维光栅等离激元结构，作为可见光中的理想窄带光吸收剂及其在葡萄糖检测中的应用。所提出的结构由金膜上电介质层顶部的一维金光栅组成。介电光栅指数（n），光栅厚度（t），光栅宽度（W）和光栅周期（P）已通过计算品质因数和品质因数（FOM）来改善等离子体结构的性能。优化的等离激元结构可作为理想的窄带光吸收器。在特定波长的灵活性，工作也由所提出的结构通过几何参数和电介质光栅的折射率的适当选择所提供。等效的RC模型用于了解光学响应上所提出结构的不同组件。结构的吸收响应对于入射角是不变的。此外，拟议的等离激元结构的计算吸光度约为100％，而窄的全宽半最大值（FWHM）约为2.8 nm。