Highly Sensitive Surface Plasmon Resonance Refractive Index Multi-Channel Sensor for Multi-Analyte Sensing

In this work, we propose a simple yet highly sensitive multi-channel hexagonal photonic crystal fiber (PCF) based surface plasmon resonance (SPR) refractive index (RI) sensor for detecting multiple analytes. The target analytes and the plasmonic materials, such as, gold (Au), Au with Tantalum Pentoxide (Ta ₂ O ₅ ) and Au with Titanium Dioxide (TiO ₂ ) are employed around the exterior of the sensor for the feasibility of the operation. Twelve circular air-holes in two layers constitute the fiber structure which makes the fabrication process easy and realizable. Numerical investigations are carried out employing a full-vector finite element method (FEM) to obtain the sensing performance of the PCF-SPR structure. After optimizing the structural parameters, the sensor achieves maximum wavelength sensitivity (WS) of 38100 and 21600 nm/RIU, for channels-1 and -2, respectively. For channel-3, the sensor achieves a maximum WS of 45800 nm/RIU. To the best of our knowledge, the proposed sensor achieves better performance in terms of wavelength sensitivity, wavelength resolution, amplitude sensitivity, amplitude resolution, figure of merit, etc., compared to the existing literature. In the case of cancerous cell detection, the proposed sensor achieves maximum WS and amplitude sensitivity of 12000 nm/RIU and −2440.30 RIU ⁻¹ , respectively, for HeLa cells. We envisage that the proposed sensor has a high potential to detect unknown RI for different chemical and biomedical applications due to its superior performance, simple design, and multi-analyte detection ability.