In-line microfluidic integration of photonic crystal fibres as a highly sensitive refractometer

Chuang Wu, Ming Leung Vincent Tse, Zhengyong Liu, Bai Ou Guan, Aping Zhang, Chao Lu, Hwa Yaw Tam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

35 Citations (Scopus)


Photonic crystal fibres appear to be an ideal platform for the realisation of novel optofluidic devices and sensors due to their waveguide nature and microstructured architecture. In this paper, we present the fabrication and characterisation of an in-line photonic crystal fibre microfluidic refractometer enabled by a C-shaped fibre. The C-shaped fibre spliced in-between the photonic crystal fibre and the single-mode fibre allows simultaneous in-line optical signal delivery and analyte fluid feeding. Through an arc discharge pre-treatment technique, we successfully achieve selective exploitation of only the central two channels of the photonic crystal fibre for microfluidic sensing. After constructing a Sagnac interferometer, a highly sensitive refractometer with a sensitivity of 8699 nm per RIU was achieved experimentally; this agrees very well with the theoretical value of 8675 nm per RIU. As a demonstration for label-free optical sensing application, the refractometer was used to measure the concentration of NaCl solution with a sensitivity of 15.08 nm/(1 wt%) and a detection limit of 2.3 × 10-3 wt% (23 ppm).
Original languageEnglish
Pages (from-to)5422-5429
Number of pages8
Issue number21
Publication statusPublished - 1 Jan 2014

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry


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