title: High Sensitivity Refractometer Based on TiO₂-Coated Adiabatic Tapered Optical Fiber via ALD Technology.
abstract: Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO₂) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO₂ nanofilm compared to that of silica, an asymmetric Fabry-Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO₂ nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO₂ on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373-1.3500. Due to TiO₂'s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field.
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. ss_zhu@shu.edu.cn.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. ffpang@shu.edu.cn.
authors.forename: Fufei
authors.initials: F
authors.lastname: Pang
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. sjhuang@shu.edu.cn.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Huang
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. zf-198166@sohu.com.|Hebei GEO University, 136 East Huaian Road, Shijiazhuang 050031, China. zf-198166@sohu.com.
authors.forename: Fang
authors.initials: F
authors.lastname: Zou
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. qguo@staff.shu.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. wenjx@shu.edu.cn.
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Wen
authors.affiliation: Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, 149 Yanchang Road, Shanghai 200072, China. tywang@shu.edu.cn.
authors.forename: Tingyun
authors.initials: T
authors.lastname: Wang
keywords: adiabatic tapered optical fiber; atomic layer deposition; refractometer; titanium dioxide nanofilm