SPP-based silver-insulator-silver structure for healthcare and temperature-sensing applications.

In this study, the finite element method (FEM) is employed to quantitatively evaluate a plasmonic refractive index (RI) sensor using a metal-insulator-metal (MIM) waveguide with a disk-shaped resonator and a triangular defect. We examine the effects of different geometric attributes on the transmission spectrum to enhance sensor performance. The proposed sensor demonstrates peak RI sensitivity, peak temperature sensitivity, and a figure of merit (FoM) of 1600 nm/RIU, 1.2 nm/C, and 72.9RIU-1, respectively, within the 900-2000 nm wavelength spectrum. We have analyzed the framework for potential applications such as detecting adulteration in food oils, identifying the coronavirus (COVID-19) in biological blood samples, and measuring temperature. The proposed structure exhibits advantageous traits, making it appropriate for optical integrated circuits and highly sensitive sensors in food safety, healthcare diagnostics, and temperature measurement.