Ultra-sensitive refractive index sensor based on extremely simple femtosecond-laser-induced structure

Pengcheng Chen, Xuewen Shu*, Hanyuan Cao, Kate Sugden

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We demonstrate here an extremely simple, compact and robust RI probe sensor based on a femtosecond-laser induced refractive-index-modified-dot (RIMD) fabricated near the end face of a single mode fiber. The RIMD and the fiber end face form a Fabry-Perot interferometer, which is highly sensitive to surrounding RI. The fabrication process of the RIMD involves only one step and takes ~0.1s, which is extremely short compared with other techniques. The proposed sensor exhibits an ultra-high sensitivity of ~2523.2 dB/RIU at an RI of 1.435, which is 1-2 orders of magnitude higher than that of the existing intensity-modulated RI sensors. Moreover, the proposed sensor has the distinct advantages of compact size (~50 µm), easy fabrication and no temperature cross-sensitivity. The advantages of the device make it a promising candidate for applications in designing highly sensitive sensors in biochemical and environmental measurement field.
Original languageEnglish
Pages (from-to)1157-1160
Number of pages4
JournalOptics Letters
Issue number6
Early online date13 Mar 2017
Publication statusPublished - 15 Mar 2017

Bibliographical note

© 2017 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited.


  • fiber optics sensors
  • microstructure fabrication
  • interferometry
  • Fabry-Perot
  • all-optical devices


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