title: Porous optical fibers for high-sensitivity ammonia-vapor sensors.
abstract: A new porous glass optical fiber has been developed for use as a sensor for the detection of ammonia vapors at low concentrations. The porous structure that remains after selective heat treatment, phase separation, and chemical leaching of a borosilicate glass imparts a high surface area to the fiber core. Ammonia vapors permeating into the porous zone, which is pretreated with a reversible pH dye indicator, produce a spectral change in transmission. The resulting pH change is measured by in-line optical absorbance and is proportional to the ambient-ammonia concentration. Ammonia-vapor concentrations as low as 0.7 part in 10(6) have been detected.
authors.forename: M R
authors.initials: MR
authors.lastname: Shahriari
authors.forename: Q
authors.initials: Q
authors.lastname: Zhou
authors.forename: G H
authors.initials: GH
authors.lastname: Sigel