Surface plasmon resonance based fiber optic hydrogen sensor utilizing wavelength interrogation

Abstract

In this paper we present an experimental study on the surface plasmon resonance (SPR) based fiber optic sensor for the detection of hydrogen. Wavelength interrogation mode of operation has been used for sensing. The probe is fabricated by coating silver, silicon and palladium (Pd) layers over unclad core of the fiber. The fact that the presence of hydrogen in the air around the palladium changes the dielectric functions of palladium is utilized. The SPR spectra are obtained for 100% nitrogen as well as for a mixture of 4% hydrogen and 96% nitrogen. A shift in resonance wavelength is obtained. The shift initially increases with time and then saturates. The silicon layer enhances the shift in resonance wavelength.