OPTICAL TIME-OF-FLIGHT CHEMICAL-DETECTION - SPATIALLY-RESOLVED ANALYTE MAPPING WITH EXTENDED-LENGTH CONTINUOUS CHEMICALLY-MODIFIED OPTICAL FIBERS

We theoretically evaluate and experimentally verify a novel strategy f or spatially resolved analyte mapping over extended remote areas. The approach combines a method for the fabrication of continuous extended- length sensors with optical time-of-flight chemical detection (OTOF-CD ), The use of OTOF-CD makes it possible to locate the zones in the fib er where attenuation or fluorescence takes place, to determine the mag nitude of these variations, and to relate the magnitude of the variati ons to the local concentration or concentrations of a single analyte o r several analytes. Simulation experiments suggest that OTOF-CD should provide spatial resolution close to its theoretical limit by deconvol ution of the returned wave form with all time-dependent experimental v ariables (laser pulse width, reagent fluorescence lifetime, etc.). The signal-processing technique should be useful for a wide variety of se nsors based on absorption, refractive index, or statically and dynamic ally quenched fluorescence. Experimental results with a model system ( a 48-m-long oxygen sensor) compare favorably with those predicted by n umerical simulations. Possible experimental difficulties in the realiz ation of these novel sensors are discussed as are ways to overcome the m.