Proposition and Numerical Analysis of a Plasmonic Sensing Structure of Metallo-Dielectric Grating and Silver Nano-slabs in a Metal-Insulator-Metal Configuration

Abstract

We propose and numerically investigate a near-infrared surface plasmon resonance-based refractive index sensor having in unison an extremely high sensitivity (1719 nm/RIU) and transmission efficiency (91.73%) with a high figure of merit (39.81). The proposed sensor structure, consisting of a 1D metallo-dielectric grating of silver and rectangular-shaped silver nano-slabs in a metal-insulator-metal configuration, excites both propagating surface plasmon polaritons and localized surface plasmon polaritons producing highly improved spectral response. Using the finite-difference time-domain computation method, the spectral characteristics were analyzed and some important sensing performances, such as sensitivity, transmission efficiency, full-width at half-maximum, and figure of merit, were optimized through numerical simulations as a function of the shape and size of the nanostructures. As a specific application, the proposed structure was also investigated for temperature sensing application and its temperature sensitivity is found to be much better than the state-of-the-art. The proposed sensor structure may have monumental applications in such areas as biomedical and environmental sensing applications and photonic integrated circuits.