Numerical analysis of a metal-insulator-metal waveguide-integrated magnetic field sensor operating at sub-wavelength scales

This article introduces a novel plasmonic magnetic field sensor (MFS) that utilizes a Metal-Insulator-Metal (MIM) waveguide configuration with a W-shaped cavity filled with magnetic fluid (MF). The MFS's unique design combines the advantages of plasmonic sensing, offering a promising solution for the detection of magnetic field strength. It operates based on the inherent properties of surface plasmon polaritons and the magneto-optical properties of MF, resulting in a shift in resonant wavelength. The performance of the proposed MFS has been investigated through numerical calculation employing the finite element method (FEM). Remarkably, the MFS exhibits a maximum magnetic field sensitivity of 49.11 pm/Oe, covering a detection range from 33 Oe to 200 Oe. The recorded figure of merit (FOM) and Q-factor of the MFS are 18.39 and 18.4 respectively, attesting to its high performance and reliability. This innovation has the potential to revolutionize fields such as navigation, medical diagnostics, and robotics technologies by seamlessly integrating optical sensing into traditional devices. The proposed sensor's excellent performance, compact size, and cost-effectiveness position it as a promising technology for widespread adoption, contributing to advancements in magnetic field sensing across scientific, industrial, and technological domains.