Long-range surface plasmon-polariton waveguide sensors with a Bragg gratingin the asymmetric double-electrode structure.

We propose a Bragg grating resonance sensor based on long-range surface plasmon-polaritons (LRSPP) excited on an asymmetric double-electrode waveguide structure. The proposed LRSPP waveguide sensor utilizes spectral resonance of the asymmetric double-electrode structure by adding a Bragg grating layer on the top surface of the metal slab. We have numerically estimated the bulk index resolution and thickness detection limit of a target biomolecule layer under 30 dB total propagation loss. The sub-mum fluidic channel between the two metal layers always experiences a highly confined LRSPP mode excited by end-fire coupling with optical fibers, therefore the proposed LRSPP sensor platform can be applied to a variety of integrated sensor-chip scenarios.