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Proceedings Paper

Fiber optic fluorescence sensors based on sol-gel entrapped dyes
Author(s): Brian D. MacCraith; Vincent P. Ruddy; C. Potter; John F. McGilp; Brendan O'Kelly
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Paper Abstract

Many fiber optic sensors for chemical species rely on a change in the fluorescence characteristics of a dye in response to its chemical environment. Such sensors often require the complex immobilization of the fluorescent species on or near the fiber surface. A novel process, whereby a highly transparent porous glass can act as a support for sensor dyes, is presented. The sol-gel process for low-temperature fabrication of porous glass has been used as a means of entrapping chemically-sensitive dyes for fiber optic sensor applications. As a proof of principle, fluorescein dye was used to investigate the performance of a pH sensor. Because of its potential for distributed sensing and planar integrated optics sensors, evanescent-wave rather than direct excitation of fluorescence was used. A short length of unclad fiber was coated with a thin layer of porous cladding within which the pH-sensitive dye is entrapped. The sensor displayed maximum sensitivity in the range of pH 3.5 to pH 6.5 with a response time of less than 5 seconds. The suitability of the technique for distributed and integrated-optic sensing of gaseous and liquid species is discussed.

Paper Details

Date Published: 1 September 1991
PDF: 6 pages
Proc. SPIE 1510, Chemical and Medical Sensors, (1 September 1991); doi: 10.1117/12.47129
Show Author Affiliations
Brian D. MacCraith, Dublin City Univ. (Ireland)
Vincent P. Ruddy, Dublin City Univ. (Ireland)
C. Potter, Dublin City Univ. (Ireland)
John F. McGilp, Trinity College (Ireland)
Brendan O'Kelly, Trinity College (Ireland)

Published in SPIE Proceedings Vol. 1510:
Chemical and Medical Sensors
Otto S. Wolfbeis, Editor(s)

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