Performance evaluation of a bilayer SPR-based fiber optic RI sensor with TiO₂ using FDTD solutions

Abstract

We proposed a new bilayer surface plasmon resonance-based fiber-optic refractive index sensor with silver and an over-layer of TiO₂. We numerically investigated the optimal thickness of TiO₂ over-layer in the proposed sensor and compared its performance to that based on typical bimetallic layers of silver-and-gold in the aqueous media using finite-difference time domain approach. We show that the use of TiO₂ over-layer greatly improves the sensor performance in terms of sensitivity and signal-to-noise ratio compared to that with gold as the over-layer. Not only does the TiO₂ over-layer offer a cost-effective alternative to gold for overcoming the oxidation problem, but also it allows resonance wavelength-tunability.

Keywords

Bilayer / surface plasmon resonance (SPR) / fiber optic sensor / refractive index (RI) / finite-difference time domain (FDTD)

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