Design and Analysis of Aluminum-Silicon-Graphene Based Plasmonic Device for Biosensing Applications in the Optical Communication Band

Abstract

This work utilizes the modified Attenuated Total Reflection (ATR) configuration, to detect minute refractive index changes near the sensing surface. In the proposed ATR configuration, the presence of the graphene layer increases the interaction with bio-analyte by adsorbing the biomolecules and the presence of a thin silicon layer helps to enhance the sensitivity of the proposed device. The use of aluminum as the plasmonic metal serves an economical value as well as compatibility with the optoelectronic devices. All the geometrical parameters of the layers over the base index prism are engineered for maximum sensitivity and narrow linewidth in the optical communication band using the transfer matrix method. The stacking of silicon-graphene layers over the thin metal-coated glass prism leads to the maximum sensitivity of 200°/RIU and figure of merit of 95.23 RIU−1 at the wavelength of 1550 nm. To demonstrate the proposed device as a bio-sensor, rodent urine is considered as the analyte under test to detect the changes in the varying concentration of Leptospira bacterium. The proposed plasmonic device opens a new window for the detection of biomolecular interactions in the optical communication band.