Ultrahigh resolution integrated optic short range surface plasmon-polariton based sensor for aqueous environment

Abstract

Abstract We propose a short length plasmonic integrated optic sensor with ultrahigh sensitivity and resolution for aqueous environment. The sensor section is a simple multilayer structure consisting of a dielectric planar waveguide separated from a thin metal film by a low index buffer layer. The sensor is based on the hybrid coupling between the guided mode and the short range plasmonic mode supported by the thin metal film. Periodic coupling between these modes takes place along the length of the sensor. For optimized layer thicknesses, resonant peak appears at very short length of sensing section. The spectral position of resonant peak is strongly dependent on the analyte index. We show theoretically that a spectral sensitivity of 3.2 × 104 nm RIU−1 with FWHM of 2 nm and resolution of 6.2 × 10–8 RIU can be achieved for aqueous environment.