Design and characterization of highly sensitive plasmonic sensor for pathogens detection in water

The photonic crystal fiber (PCF) based plasmonic sensors have drawn incredible attention from researchers in many research disciplines due to their versatility, quick response, label-free detection, design freedom, and low weight. Here, a gold-coated hexagonal lattice PCF sensor having an external analyte detection facility is proposed using the surface plasmon resonance (SPR) technology. The design and performance optimization of the proposed sensor has been completed using commercially available COMSOL Multiphysics 5.5. Firstly, design parameters were optimized by varying one parameter at a time then the sensor performance was calculated using well-known intensity and wavelength interrogation techniques in the analyte refractive index (RI) ranging from 1.33-1.405. Excellent amplitude sensitivity (AS), (609.023 RIU-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text {RIU}<^>{-1}$$\end{document}), and wavelength sensitivity (WS), (18,000 nm/RIU), along with an outstanding resolution (5.56x10-6\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$5.56 \times 10<^>{-6}$$\end{document} RIU), are attained with optimum design parameters. Secondly, the sensor performance is carried out with four bacteria (common pathogens in water) such as Enterococcus faecalis, Escherichia Coli (E. coli), Vibrio Cholera, and Bacillus Anthracis, and the sensor exhibits tremendous WS (nm/RIU) and AS (RIU-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text{RIU}<^>{-1}$$\end{document}) of 7317.07 and 918.77, respectively. Owing to its straightforward design and high sensitivity, the proposed sensor can be effectively applied in any healthcare system to ensure safe drinking water.