Sensors 2010, 10(3), 1716-1742; https://doi.org/10.3390/s100301716
Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy
Queen’s University, Department of Chemistry, Kingston, ON, K7L 3N6, Canada
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Received: 15 December 2009 / Revised: 23 January 2010 / Accepted: 6 February 2010 / Published: 2 March 2010
(This article belongs to the Special Issue Laser Spectroscopy and Sensing)
Abstract
Waveguide-based cavity ring-down spectroscopy (CRD) can be used for quantitative measurements of chemical concentrations in small amounts of liquid, in gases or in films. The change in ring-down time can be correlated to analyte concentration when using fiber optic sensing elements that change their attenuation in dependence of either sample absorption or refractive index. Two types of fiber cavities, i.e., fiber loops and fiber strands containing reflective elements, are distinguished. Both types of cavities were coupled to a variety of chemical sensor elements, which are discussed and compared. View Full-TextKeywords:
cavity ring-down (CRD); absorption; refractive index; fiber-loop; fiber cavity; microfluidics; capillary electrophoresis; phase-shift; long-period grating (LPG); fiber Bragg grating (FBG)
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