WITHDRAWN: Application of FTO and FTO/HfO2 bilayers in Lossy Mode Resonance based fiber optic sensors

Abstract

• A fiber optic refractive index sensor based on LMR phenomenon is proposed. • Layers of Fluorine-doped Tin Oxide (FTO) and FTO/HfO 2 bilayers are used. • Sensitivity is found to be 4075.71nm/RIU of the bilayer of FTO and HfO 2. • It is more than six times the sensitivity of only FTO based LMR sensor. • It is approximately eight times greater than the AZO based tapered fiber probe. The design of a highly sensitive, low-cost refractive index sensor is analysed numerically. The study is a theoretical modelling of a fiber optic refractive index sensor based on the phenomenon of Lossy Mode Resonances (LMRs). It focusses on the estimation of the maximum sensitivity value utilizing a layer of Fluorine-doped Tin Oxide (FTO) and FTO/HfO 2 (hafnium oxide) bilayer with optimised thickness of 400nm. Effect of film thickness on the sensitivity of the sensor and appearance of LMRs with increasing film thickness from 100nm to 700nm is also studied. The maximum sensitivity of the bilayer with total thickness of 400nm is found to be 4075.71nm/RIU, which is more than six times the sensitivity of only FTO based LMR sensor and approximately eight times greater than the Aluminium-doped zinc oxide (AZO) tapered fiber probe. Power loss reduction of 1.75 times can also be observed for the bilayer coated probe.