Open AccessSensitivity enhancement of a fiber-based interferometric optofluidic sensor
Author(s) -
Lili Liang,
Chenkai Zhao,
Fei Xie,
Li-Peng Sun,
Yang Ran,
Long Jin,
BaiOu Guan
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.400325
Subject(s) - microfiber , optofluidics , materials science , optics , sensitivity (control systems) , interferometry , refractive index , optical fiber , microfluidics , photonics , fiber optic sensor , optoelectronics , nanotechnology , physics , electronic engineering , engineering , composite material
Optofluidic sensors, which tightly bridge photonics and micro/nanofluidics, are superior candidates in point-of-care testing. A fiber-based interferometric optofluidic (FIO) sensor can detect molecular biomarkers by fusing an optical microfiber and a microfluidic tube in parallel. Light from the microfiber side coupled to the microtube leads to lateral localized light-fluid evanescent interaction with analytes, facilitating sensitive detection of biomolecules with good stability and excellent portability. The determination of the sensitivity with respect to the interplay between light and fluidics, however, still needs to be understood quantitatively. Here, we theoretically and experimentally investigate the relationship between refractive index (RI) sensitivity and individual geometrical parameters to determine the lateral localized light-fluid evanescent interaction. Theoretical analysis predicted a sensitive maximum, which could be realized by synergically tuning the fiber diameter d and the tube wall thickness t at an abrupt dispersion transition region. As a result, an extremely high RI sensitivity of 1.6×10 4 nm/RIU (σ=4074 nm/RIU), an order of magnitude higher than our previous results, with detection limit of 3.0×10 -6 RIU, is recorded by precisely governing the transverse geometry of the setup. The scientific findings will guide future exploration of both new light-fluid interaction devices and biomedical sensors.