Highly Sensitive MIM-Based Semi-circular Refractive Index Sensor for Detection of Glucose Concentration

Abstract

This article presents and numerically investigates a semi-circular, highly sensitive refractive index sensor using a Metal-Insulator-Metal (MIM) waveguide structure comprising a baffle. Specifically designed cavities hold the material under sensing (MUS), and silver is utilized to fill the surrounding area. The Finite Element Method (FEM) is used to simulate the intended model, which exhibits the linear relationship between the refractive index and the corresponding shift of the resonant wavelength. The sensor can identify unknown materials and glucose concentration by utilizing this linearity of peak changes. By tuning the structural parameters to an optimized value, a maximum sensitivity of 4859 nm/RIU is achieved for the refractive index range of 1.5 to 1.6. Moreover, the sensor exhibits a high sensitivity of 4255 nm/RIU for detecting different ranges of concentrated glucose solution. Hence, the sensor is a promising option for on-chip bio-sensing and chemical applications because of its extremely high sensitivity, straightforward architecture, cost-efficiency, and performance as a glucometer.