In this paper, we demonstrate a dual-band tunable absorber coupled with a nanoscale metal-dielectric-metal (MDM) structure for sensing applications in the near-infrared spectral region. This structure exhibits a dipole resonance mode in absorbance and reflectance spectra which results in the enhancement of absorbance over a wide range of incident angles for TE polarization. Using a numerical and analytical study, the performance parameters of the structure including sensitivity (SS), the figure of merit (FoM) and quality factor (Q) are investigated by changing the incident polarization, geometrical parameters, filling dielectric and plasmonic metasurface material. Moreover, we study the dependence of the sensitivity as a function of plasmonic metasurface shape to demonstrate a better response compared with other methods. Results show that, in terms of the refractive index unit (RIU), an ultra-high sensitivity and tunable sensor can be designed with a maximum sensitivity of 1240.8 nm/RIU for a refractive index change of Δn = 0.0458. In the optimum design of the proposed dual-band absorber, a Q-factor and FoM equal to 123.45 and 44.5 are obtained. Furthermore, the proposed structure can be utilized for controlling the light propagation. By considering silver as a plasmonic metasurface, a slow down factor as high as 680 is obtained. Our work will be applied to future sensors capable of ultra-high sensitivity.

在本文中，我们演示了一种双波段可调谐吸收器，结合了纳米级金属-电介质-金属（MDM）结构，可用于近红外光谱区域中的传感应用。这种结构在吸收光谱和反射光谱中表现出偶极共振模式，这导致TE偏振在较大入射角范围内吸收率提高。通过数值和分析研究，通过改变入射极化，几何参数，填充电介质和等离子超表面材料，研究了结构的性能参数，包括灵敏度（SS），品质因数（FoM）和品质因数（Q）。此外，我们研究了灵敏度与等离子元表面形状的关系，以证明与其他方法相比具有更好的响应。结果表明，n  = 0.0458。在建议的双频带吸收器的最佳设计中，获得了Q因子和FoM等于123.45和44.5。此外，所提出的结构可以用于控制光传播。通过将银视为等离子超表面，可获得高达680的减速因子。我们的工作将应用于未来具有超高灵敏度的传感器。