Theory and FDTD simulations of an amorphous silicon planar waveguide structure suitable to be used as a surface plasmon resonance biosensor

In this paper we present our work concerning the design of a semiconductor waveguide structure to be used as a biosensor based on Surface Plasmonic Resonance effects (SPR). The proposed structure is a planar metal-dielectric waveguide where the sensor operation is based on the coupling between the fundamental propagation TM mode and the surface plasmon excited at the outer boundary of the metal, which interfaces the sample medium. Gold and aluminium are the metals considered for the plasmonic coating, amorphous silicon and a reduced graphene oxide layer are considered for the waveguide structure. FDTD simulations of the proposed structure show a clear attenuation peak in the output power at the wavelength where the plasmonic resonance is excited.