Theoretical modelling of a deformation based concave square ring-square disc (SR-SD) silver structure for pressure sensing

Abstract

A compact nanosensor that explores the tie-in between stress-induced deformation and optical resonance characteristics is theoretically proposed for pressure sensing. The structure modeling, electromagnetic (EM) wave simulation, and performance evaluations were carried out using the 2D finite element method (FEM). The proposed surface plasmon resonance (SPR) based metal-insulator-metal (MIM) model responds to the pressure induced on the top-facing side of an Ag concave square ring-square disc arrangement (Concave SR-SD) in terms of a structural curve-in into the insulator cavity. These deformations alter the electromagnetic field distributions and plasmonic resonance conditions, shifting the absorption cross-section profiles towards higher wavelengths. The shift in the resonant wavelength (Δλ) for specific measured deformations (d) exhibited by the normal SR-SD hinds at the application level perspective of the designed system in pressure sensing via its optomechanical correlation. Further, multiple parameters like insulator cavity width (W I ) and structure wise modifications in the outer ring structure are investigated for performance optimization, and subline sensitivity values (maximum) of 24.496 nm/MPa and 40.46 nm/MPa are observed from normal and concave SR-SD systems respectively. The suggested nano pressure sensor of suitable sensitivity and broad sensing range promises strong applicability in biomedicine, health monitoring, nanomechanics, chip-based devices, and nanoelectronics.