Fano resonance and plasmon-induced transparency in waveguide-coupled surface plasmon resonance sensors

A planar multilayer structure that allows coupling between surface plasmon polaritons and waveguide modes is proposed. Calculated reflectivity curves exhibit sharp resonances due to the Fano resonance and plasmon-induced transparency arising from the coupling. Electric field profiles obtained at the resonances demonstrate the hybrid nature of the modes excited. When the Fano resonance is used for sensing, the sensitivity with intensity modulation is enhanced by two orders of magnitude relative to that of conventional surface plasmon resonance sensors.