Long Range Surface Plasmon Resonance Based Taper Fiber Optic Sensor with Enhanced Sensitivity using Au Nano-Layer through Radially Polarized Light

Abstract

A new theoretical approach towards the sensitivity enhancement of tapered fiber optic sensor based on the long range surface plasmon (LRSP) resonance technique in Teflonmetal coated tapered fiber structure using radially polarized is proposed, designed and simulated within Kretschmann-Raether geometry. The configuration comprising a fiber core coated with 690 nm and 70 nm thin Teflon layer and Au layer respectively where the uniform taper waist having diameter 330 µm and 350 µm with taper ratio of 1.7 (NA: 0.25, 10 mm long waist region) and a sensing layer having varying refractive index from 1.333 to 1.353. With the increase in refractive index the observed results indicates a 1.7 times better sensitive tapered fiber sensor as compared to the existing LRSP based fibre optic sensors using intensity interrogation technique. To the best of our knowledge several articles have been devoted in the field of LRSP based fibre optic sensor with p-polarized light whereas no such article has yet been reported with Teflonused as a dielectric between metal coated taper fiber optic sensors using radially polarized light with better sensitivity. Here sensitivity also analysed w.r.t wavelength interrogation technique where the sensitivity enhancement is about 1.7 times than the existing fiber optic sensors.