title: High sensitivity refractive index sensor based on adiabatic tapered optical fiber deposited with nanofilm by ALD.
abstract: Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractive index sensor based on an adiabatic tapered optical fiber. Different thickness of Al2O3nanofilm is coated around fiber taper precisely and uniformly under different deposition cycles. Attributed to the high refractive index of the Al2O3nanofilm, an asymmetry Fabry-Perot like interferometer is constructed along the fiber taper. Based on the ray-optic analysis, total internal reflection happens on the nanofilm-surrounding interface. With the ambient refractive index changing, the phase delay induced by the Goos-Hänchen shift is changed. Correspondingly, the transmission resonant spectrum shifts, which can be utilized for realizing high sensitivity sensor. The high sensitivity sensor with 6008 nm/RIU is demonstrated by depositing 3000 layers Al2O3nanofilm as the ambient refractive index is close to 1.33. This high sensitivity refractive index sensor is expected to have wide applications in biochemical sensors.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhu
authors.forename: Fufei
authors.initials: F
authors.lastname: Pang
authors.forename: Sujuan
authors.initials: S
authors.lastname: Huang
authors.forename: Fang
authors.initials: F
authors.lastname: Zou
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Dong
authors.forename: Tingyun
authors.initials: T
authors.lastname: Wang