Surface plasmon-polariton Mach-Zehnder refractive index sensor

Abstract

We present what we believe is a novel theoretical scheme for phase interrogation of a planar refractive index sensor based on a surface plasmon polariton (SPP) excited with a Bragg grating. The device is a Mach-Zehnder interferometer (MZI), which offers a simple integrated optical solution to monitor relative phase variations in waveguides. The principle of operation for this device is based on the significant phase change in the field of a waveguide mode transmitted through a grating. This phase change occurs during the SPP excitation and is caused by the change in the refractive index of the sensed layer in contact with the metal layer supporting the SPP, operating at commercialized telecommunications wavelengths.