Photonic spin Hall effect-based ultra-sensitive refractive index sensor for haemoglobin sensing applications

A highly sensitive Photonic Spin Hall Effect (PSHE)-based layered sensor is proposed which detects changes in refractive index of biological sample. A simple and elegant design measures haemoglobin concentrations using Surface Plasmon Resonance (SPR) effect. It consists of a BK7 prism, a thin gold layer, an analyte layer of haemoglobin and BK7 glass as the substrate. The average angle sensitivity (SR) has been calculated and found to be 191°/RIU, 208°/RIU and 171°/RIU respectively for low, normal and high haemoglobin concentrations. The Figure of Merit (FOM) for the proposed structure is found to be 896RIU-1, 812RIU-1 and 3166RIU-1 respectively for low, normal and high concentrations of oxygenated haemoglobin.