Ultrasensitive plasmonic sensor based on MDM waveguide containing Persian Orsi window cavities for refractive index and blood plasma sensing

We developed a plasmonic refractive index (RI) with a metal-dielectric-metal (MDM) structure that utilizes two Persian Orsi windows-like separated cavities with a high figure of merit (FoM) and ultrasensitivity. The simulated and optimized Ag-air-Ag MDM sensor for surface plasmon resonance (SPR) offers high RI sensitivity (S_RI) and the ability to detect blood plasma concentration (BPC). The results verified that structural parameters have an effect on S_RI, full width at half maximum (FWHM), FoM, sensitivity of blood plasma (S_p) for right and left peaks, whose values are 1 345.45 nm·RIU⁻¹, 32 nm, 42.04 RIU⁻¹, 0.26 and 0.19 nm·L·g⁻¹, respectively. The proposed design opens a new horizon in sensor development.