Hybrid waveguide based long-range surface plasmon biosensor

An integrated hybrid waveguide coupled long range surface plasmon polaritons (LRSPPs) biosensor is proposed and analyzed by the Finite Element Method (FEM). The influence of the structural parameters on the coupling between the dielectric waveguide (DWG) and LRSPPs modes are numerically investigated. Simulation results show that the resonant coupling wavelength between the DWG and LRSPPs modes is very sensitive to small refractive index changes i.e. the estimated sensitivity is as high as 4180 nm/RIU (refractive index unit). Furthermore, when operating in intensity interrogation, its detection of limit has been shown as small as 3.7 x 10-7 RIU