To achieve sensing of low refractive indexes (RIs) in the near-infrared region, a novel series-wound structure with dual gold nanowires is designed and the photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is investigated. Numerical simulation by the finite element method (FEM) reveals that the odd mode for y-polarization has better sensing properties due to the more prominent shift of the confinement loss peak. The PCF-SPR sensor can realize a broad range of detection for low RIs changing from 1.13 to 1.35. The maximum spectral sensitivity of 17500 nm/RIU and optimal resolution of 5.71 × 10⁻⁶ RIU are observed for RIs between 1.34 and 1.35. Thus, the proposed sensor can be applied in environmental engineering, biochemical analysis and healthcare fields due to its ultrahigh sensitivity for analytes with low RIs in the near-infrared region and fabrication simplicity.

为了实现在近红外区域的低折射率（RI）传感，设计了一种具有双金纳米线的新型绕线结构，并研究了基于表面等离子体共振（SPR）的光子晶体光纤（PCF）传感器。有限元方法（FEM）的数值模拟表明，由于限制损耗峰的移动更加明显，因此用于y极化的奇数模式具有更好的感测特性。PCF-SPR传感器可实现从1.13到1.35的低RI的广泛检测范围。最大光谱灵敏度为17500 nm / RIU，最佳分辨率为5.71×10 ^-6RI介于1.34和1.35之间。因此，由于该传感器对近红外区域中具有低RI的分析物具有超高灵敏度，并且制造简单，因此可以应用于环境工程，生化分析和医疗保健领域。