Design and Analysis of a U-Shaped Optical Fiber-Based Plasmonic Sensor for Detection of Cancer Cells

In this article, we aim to put forward a simple, cost-effective, compact, and high-performance optical fiber biosensor for the detection of numerous cancer cells in the human body. The proposed sensor is grounded on a multimode optical fiber with an Au-coated U-shaped core. The designed optical fiber sensor (OFS) is modelled and analyzed exploiting finite element method (FEM)-based COMSOL Multiphysics. The working principle of the sensor is based on surface plasmon resonance (SPR) phenomenon excited on the surface of Au layer, which leads to generation of strong evanescent field near the sensing area. The backbone of this study is to investigate the coupling of plasmonic mode and core mode to get a maximum confinement loss, which intensifies the evanescent field near the sensing region. Numerous geometrical parameters such as thickness of Au layer, height of the channel, and width of the channel are carefully adjusted to accomplish optimum performance. The numerical simulation outcomes reveal that the proposed sensor can achieve a maximum sensitivity of 2352.94 nm/RIU, figure of merit of 24.15 1/RIU, and resolution of 4.3x10-6\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$4.3\times {10}<^>{-6}$$\end{document} RIU. Above all, the proposed sensor is miniature in size, easy to fabricate, and facilitates real-time sensing of cancer cells, which can be a suitable candidate for bio-medical applications.