Plasmonic Sensor with BaTiO3 and Si Layers for Dual Application in Environmental Monitoring

Abstract

The need of environmental monitoring with the advancement and climate emergency is vital for the survival. The use of preservatives, fertilizers, cooling substances, etc., either in aqueous or in gaseous form has been increased in daily life. Therefore, it is important to develop a sensor which can sense both to monitor these. The present study provides a theoretical approach to achieve refractive index sensing based surface plasmon resonance sensor to monitor gaseous and aqueous impurities with a single probe. Use of fiber optic-based SPR sensor provides remote sensing, compact design, and real time monitoring, etc. The proposed sensor is optimized to sense both aqueous and gaseous analyte medium. The use of BaTiO₃ and Si layer provides multi-fold improvement in sensitivity in NIR region. For proposed sensor, we have achieved ultrahigh sensitivity and good figure of merit for aqueous medium ranging from RI 1.33 to 1.37 and high sensitivity with linear performance for gaseous medium. For gaseous analyte, the sensor is working for ultralow concentration ranges up to RI 1.01. Hence, the proposed sensor will be beneficial for both the aqueous and gaseous impurity monitoring in NIR region where it shows linear performance throughout the range of gaseous refractive indices analyte.