High sensitivity SPR sensor for liquid phase sample with Ag/PbS/Graphene hybrid nanostructure

Abstract

A surface plasmon resonance (SPR) sensor with Ag/PbS/GR hybrid nanostructure has been proposed for the diagnostics of liquid phase samples. Here Ag/PbS/GR hybrid nanostructure is designed as an asymmetric MIM waveguide for surface plasmon. Due to the guided wave SPR (GWSPR) modes, the index of the liquid phase samples can be measured more accurately than the conventional SPR sensors. Numerical simulation results show that the sensitivity of the sensor is about 5 times higher than the conventional SPR sensors. The origin of the enhancement mechanism is the combination of GWSPR in the Ag/PbS/GR hybrid nanostructure which enables the surface plasmon to spread along the PbS layer. In Ag/PbS/GR hybrid nanostructure, the electric field is concentrated mostly in the PbS layer, and the enhancement of the field intensity is nearly 30%.