Hetero-core fiber optic LSPR sensor based on TiO2 and Au island films for refractive index measurement

In this paper, we propose a hetero-core optical fiber with a high refractive index material, TiO₂, deposited on the inner layer of the Au island films, which is fabricated by sputtering method and annealing. It was confirmed that this structure of TiO₂ deposited on the inner of the Au island films strongly excites the absorption peak in the visible light region and detects the refractive index change in the near-infrared region compared to the conventional hetero-core optical fiber sensor using Au island structure.