Silicon carbide based surface plasmon resonance waveguide sensor with a bimetallic layer for improved sensitivity

In this letter, silicon carbide (SiC) waveguide based surface plasmon resonance optical sensor with an Ag-Au bilayer metal configuration was studied. The wide bandgap energy of SiC allows the sensor to operate in visible and near-infrared range. The spectrum of resonant wavelength with refractive index shows improved sensitivity and sensing resolution in the Au-Ag bilayer configuration than in the single Au layer configuration. A sensitivity of 2581 nm/RIU (refractive index unit) indicated by the shift of resonant wavelength with refractive index was observed from a refractive index range of n=1.34-1.36, showing that the sensor is desirable for sensing in a series of biological analytes interesting to research, such as Hepatitis B virus (HBV), glucose, etc.