In this paper, a highly sensitive plasmonic refractive index (RI) sensor based on photonic crystal fiber (PCF) is proposed. Silver (Ag) is used as plasmonic material and tantalum pentoxide (Ta₂O₅), high RI material, is used as an overlayer over the silver thin film. The sensor performance is realized using surface plasmon resonance (SPR) phenomenon. The effect of tantalum pentoxide overlayer thickness on sensing parameter as well as on sensitivity is analyzed in detail using finite element method (FEM). The detailed study shows an interesting property that the increasing Ta₂O₅ layer thickness can tune the operating analyte RI from high RI region to low RI region i.e. towards the aqueous medium. The structural parameters of the proposed sensor are being optimized and its sensitivity is realized using wavelength interrogation technique. A maximum sensitivity of 50000 nm/RIU is reported. This study, no doubt, provides a new direction of designing RI sensor that could tune RI range by varying the only the Ta₂O₅ layer thickness to the desired operating analyte region. Besides, the simple design feasibility, low fabrication cost and portable nature of the proposed sensor make it suitable for industrial and chemical sensing applications.

本文提出了一种基于光子晶体光纤（PCF）的高灵敏度等离激元折射率（RI）传感器。银（Ag）被用作等离子体材料，高RI材料五氧化_二钽（Ta ₂ O ₅）被用作银薄膜上的覆盖层。传感器的性能是通过表面等离振子共振（SPR）现象实现的。使用有限元方法（FEM）详细分析了五氧化二钽覆盖层厚度对传感参数以及灵敏度的影响。详细的研究显示出一个有趣的特性，即增加的Ta ₂ O ₅层厚度可以将运行中的分析物RI从高RI区调整到低RI区，即。朝向水性介质。拟议中的传感器的结构参数正在优化，其灵敏度是通过波长询问技术实现的。据报道最大灵敏度为50000 nm / RIU。毫无疑问，这项研究为设计RI传感器提供了新的方向，该传感器可以通过仅将Ta ₂ O ₅层的厚度更改为所需的工作分析物区域来调整RI范围。此外，所提出的传感器简单的设计可行性，较低的制造成本和便携性使其适合于工业和化学传感应用。