Performance Analysis of Surface Plasmon Resonance Based Optical Fiber Sensors

Abstract

Over the past few decades, researchers have shown immense interest in new technology, named Surface Plasmon Resonance (SPR) which utilizes the fascinating light-matter interaction involved at a metal-dielectric interface. This technology is employed for fast and accurate measurement of various physical, chemical and biochemical parameters. The benefits of the SPR based fiber optic sensor are miniaturization of the probe and its utilization in remote sensing applications that is not achievable with prism based SPR sensor.

The objective of this dissertation is to analyze the performance of SPR based optical fiber sensors and for this purpose Opti-Finite Difference Time Domain (FDTD) software is used which allows the design of different configurations SPR sensors.

First study presents the theoretical investigation on the effect of different mode profiles on the guiding region of SPR based optical fiber sensor having gold coated fiber core. Transmission spectra for different transverse magnetic (TM) modes are also compared with respect to the operating wavelength.

Further this dissertation is focused on the theoretical studies of SPR based fiber optic sensors with different materials for sensitivity enhancement. In another study, theoretical analysis of SPR based fiber optic sensor with tri-layer of ITO-Ag-TiO2 has been performed. The SPR sensor shows high performance characteristics in comparison of bi-layer (ITO-Au) based SPR sensor. Besides it, minima in transmittance curve also dependent on the thickness of the outer layer as well as on middle metal layer used in sensor design.

Finally, the theoretical analysis has been extended to SPR based fiber optic sensor with TCOs (AZO/GZO). The proposed SPR sensor is observed to have high sensitivity and good response as compared to conventional Au/Ag metal-deposited SPR sensors. The benefits of the proposed SPR based fiber optic sensor are low intrinsic loss, semiconductor-based design, compatibility with standard nanofabrication processes, tunability etc. over the conventional metals based SPR sensors.