Sensitivity enhancement of surface plasmon resonance based fiber optic refractive index sensor using an additional layer of zinc oxide

Abstract

We have experimentally demonstrated the role of the high index dielectric layer of zinc oxide over the metal layer on the performance of the surface plasmon resonance based fiber optic refractive index sensor. The configuration contains copper as a SPR active metallic layer covered by dielectric layer. The configuration of Cu/ZnO shows high sensitivity. Further increase in the thickness of ZnO layer increases the sensitivity of the sensor. A good agreement between experimental results and the simulated ones based on multilayer two dimensional approach is obtained. The additional advantages of ZnO layer, apart from sensitivity enhancement, are protection of metallic layer from oxidation, tunability of the resonance wavelength region, biocompatibility and capability of gas sensing.