Exploration of LSPR-based Refractive Index Sensor Coated with Silver-MgF2 Layer.

A refractive index (RI) sensor has been demonstrated and numerically analyzed by the finite element method (FEM) to gain supreme sensitivity on the basis of localized surface plasmon resonance (LSPR). Plasmonic material, such as silver, has been used as a coating layer outside of the dielectric core. Various structural parameters have been analyzed for the proposed sensors, which have a significant influence on the sensing field. To make the sensing strength much stronger, a thin MgF2 layer has been added to the silver layer. The wavelength and amplitude interrogation method achieves extremely high wavelength sensitivity (WS) responses of 948.67 μm/RIU and amplitude sensitivity (AS) responses of − 1602.82 RIU−1 in the analyte RI range of 1.35 to 1.38. The operating wavelength range of 5.5–7.5 μm shows efficient results in this structure. The proposed sensor is used for identifying analytes in the biological and biochemical fields and is also applicable in bio-photonics. Owing to its low confinement losses and simply designed structure, the proposed RI sensor will be extensively appropriate for bio-sensing because of its outstanding sensitivity response. [ABSTRACT FROM AUTHOR]