Reduction of angular dip width of surface plasmon resonance sensor by coupling surface plasma waves on sensing surface and inside metal–dielectric–metal structure

Abstract

A surface plasmon resonance (SPR) scheme was developed using a metal/dielectric/metal (MDM) structure. The surface plasma wave (SPW) dispersion curves within the MDM structure can be controlled by tuning the dielectric layer thickness. Therefore, the properties of the SPWs on the sensing surface of the SPR sensor can be tuned by coupling the tunable odd SPWs in the MDM structure to the sensing SPWs. The proposed tuning procedure was based on the tendency for anticrossing formation to occur between two nonparallel dispersion curves, and the reduction in the angular dip widths of the SPR sensors using the proposed procedure was demonstrated both numerically and experimentally.