Characterization of long pathlength capillary waveguides for evanescent fluorescence sensing applications

E. D. Paprocki, B. K. Keller, C. P. Palmer, W. R. Laws, M. D. DeGrandpre

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The optical properties of a novel fused silica fiber-optic capillary (FOCap) waveguide for fluorescence chemical sensing are evaluated. Evanescent fluorescence from samples contained in the FOCap is measured by coupling the FOCap to a light source and a fluorescence spectrophotometer. The FOCap has negligible excitation light loss over long lengths (tested to 20 m). Evanescent fluorescence is linear in FOCaps up to 20 m long when filled with a fluorophore solution and up to 15 m when a fluorophore is covalently attached to the inner surface. Evanescent fluorescence measurements in 50, 150, and 250 μm inner diameter FOCaps indicate that greater sensitivity is achieved with thinner-walled capillaries which have more internal reflections. The ability of the waveguide to function as an indirect chemical sensor for nitroaromatic compounds is demonstrated via fluorescence quenching of a pyrene-labeled FOCap.

Original languageEnglish
Pages (from-to)145-151
Number of pages7
JournalSensors and Actuators, B: Chemical
Issue number1
StatePublished - Dec 10 2008


Special thanks are given to Ruben Darlington and Cory Beatty from The University of Montana and Troy Alexander from the Army Research Laboratory. This research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-04-2-0043. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing official policies, either expressed or implied, of the Army Research Laboratory or the US Government. The US Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation hereon.

FundersFunder number
United States Army Research LaboratoryW911NF-04-2-0043


    • Capillary waveguide
    • Evanescent wave fluorescence spectroscopy
    • Long pathlength


    Dive into the research topics of 'Characterization of long pathlength capillary waveguides for evanescent fluorescence sensing applications'. Together they form a unique fingerprint.

    Cite this