Exploring the Diverse Applications of Plasmonic Refractive Index Sensors: Unveiling a New Realm of Possibilities

Abstract

This research provides an overview of the design, fabrication, and applications of plasmonic nanosensors, highlighting their unique capabilities in detecting and analyzing molecular interactions at the nanoscale. A plasmonic refractive index nanosensor is a device that utilizes the interaction of light with metallic nanoparticles to detect and quantify changes in the refractive index of the surrounding medium, enabling highly sensitive and label-free detection of various analytes. They use surface plasmon polariton (SPP) and as per lightmatter interaction, they provide optical response depending on the quantity to be sensed. In this paper, three plasmonic refractive index sensor designs are proposed. The sensors have been evaluated with the finite element method (FEM) with scattering boundary conditions. The theoretical background of the functionalities and properties of plasmonic materials is explained. A plasmonic refractive index nanosensor with a modified rectangular resonator with baffles and nanorod has been proposed and it exhibits maximum sensitivity of 2963.73 nm/RIU and FOM of 25.1. Another plasmonic nanosensor design with an opposingface-semi-circular ring resonator integrated with nanorods has been proposed and it exhibits maximum sensitivity of 2975.96 nm/RIU and the recorded maximum FOM is 43.95. Lastly, another novel plasmonic nanosensor design with a modified octagonal resonator embedded with silver nanorods is proposed and as per the numerical investigation, it exhibits maximum sensitivity of 2527.6 nm/RIU with a corresponding FOM value of 16.24. The linear relationship of resonant wavelength with the refractive index has been used in advantage to detect unknown materials. Thus the application of these nanosensor designs in the medical and healthcare sectors e.g. diabetes detection, anemia detection, and classification of cancer cells are investigated. Furthermore, the application of nanosensors in the environment and safety applications are explored by the detection of chemical pollutants and heavy metals in water. The potential application in the food industry has also been explored by testing the capabilities of detecting water adulteration in honey and lactose detection in solutions. The wide range of applications of plasmonic nanosensors and their fabrication process are elaborately discussed.