Highly sensitive PCF based plasmonic biosensor for hemoglobin concentration detection

The present study reports on the investigation carried out on a newly designed photonic crystal fiber (PCF) based plasmonic biosensor for label-free hemoglobin concentration detection. In the first part, a new approach is proposed to avail external sensing mechanism by introducing the solid core at fiber periphery and nanoscale gold film coating outside the fiber. By analyzing modal characteristics using finite element method (FEM), the wavelength sensitivity is found to be varied nonlinearly up to 34,800 nm/RIU within the analyte detection range of 1.34 - 1.41 RIU (refractive index unit). In later study, the proposed fiber is investigated as hemoglobin concentration sensor (HbCS) to detect unknown hemoglobin concentration. From the detail study, to calculate sensitivity of HbCS, a nonlinear equation as a function of hemoglobin concentration has been proposed to detect unknown concentration and a maximum sensitivity of 31.2 nm/g/dL is achieved. Moreover, the minimum measurable deviation of the sensor is found to be lies of the order of 10-6 with a high figure of merit (FOM) up to 229 RIU-1 representing an overall good sensing performance. The proposed plasmonic sensor provides high sensitivity, good specificity, environmental stability along with high resolution compare to other existing technologies. Therefore, this study opens an easy and reliable window for hemoglobin concentration detection in biomedical applications.