Simulation of a Self-Referenced Meta-Grating Sensor With High Figure of Merit in NIR Communication Window

A meta-grating-based surface plasmon resonance (SPR) sensor was theoretically investigated to act as a self-referenced sensor in the near-infrared region using a spectral interrogation technique. Introduction of a high refractive index (RI) dielectric material, silicon (Si) oxynitride (SiON) film, in between the dielectric metasurface and metal layer gives rise to a self-referencing operation in the sensor. The Si meta-grating excites the SPR at the metal–analyte interface which is sensitive to the changes in the RI of the analyte and the surface plasmon (SP) mode at the metal–dielectric interface remains fixed. The geometrical parameters of the proposed sensor were optimized to obtain the self-referencing operation with superior sensing performance. The self-referencing behavior considerably reduces the error contributions due to an unsteady ambience. The maximum sensitivity of this sensor has been achieved upto 1150 nm/RIU with the figure of merit (FOM) as high as
$442.31\,\,\text {RIU}^{-{1}}$
.