SPR Based Optical Fiber Refractive Index Sensor Using Silver Nanowire Assisted CSMFC

In this article, a highly sensitive surface plasmon resonance (SPR) based concave shaped refractive index sensor (CSRIS) is designed and analyzed using silver (Ag) nanowire. The SPR effect between the surface plasmon polariton (SPP) and core guided modes of the concave shape (CS) designed sensor is used to measure the variation in refractive index (RI) of analytes (n(a)). The sensing performance and the coupling properties of proposed sensor are numerically analyzed using finite element method (FEM) based on COMSOL Multiphysics. Results exhibit a high wavelength and amplitude sensitivity of 9314.28 nm/RIU and 1494 RIU-1, respectively for the RI varying between 1.33 to 1.38 with the resolution of $1.073\times 10(-5) RIU. The designed sensor is easy to fabricate as it requires the Ag nanowire to be deposited on the concave shaped microfluidic channel (CSMFC) which is later covered with measurand. various structural parameters, i.e. distance of channel from core, diameter of Ag nanowire, and channel size, are also optimized for better sensing response.