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All-fiber online Raman sensor with enhancement via a Fabry–Perot cavity

Abstract

In this Letter, a novel all-fiber online Raman sensor with significant signal enhancement via a Fabry–Perot (FP) cavity is proposed and demonstrated. The FP cavity structure is formed by inserting a long-pass coated fiber and a gold-plated capillary into a silver-lined capillary with a gap. A corroded single-mode fiber is inserted into the gold-plated capillary to guide the excitation light into the FP cavity. The multiple reflections of excitation light in the FP cavity have significantly increased the interaction volume between the light and the sample. Experiment results have demonstrated an enhancement factor of 5 times in the detected Raman signal for ethanol compared to that measured using the silver-lined hollow-core fiber-based Raman cell without FP cavity, or 86 times compared with direct detection using a bare fiber tip. The measurement results are in good agreement with theoretical analyses. This Raman sensor with signal enhancement via the FP cavity has the potential to realize rapid sample replacement and online detection with high sensitivity and high accuracy for biochemical applications.

Category

Academic article

Language

English

Author(s)

Affiliation

  • SINTEF Digital / Smart Sensors and Microsystems
  • China
  • Nanjing University
  • Singapore

Year

2020

Published in

Optics Letters

ISSN

0146-9592

Volume

45

Issue

20

Page(s)

5760 - 5763

View this publication at Norwegian Research Information Repository