INTRINSIC SOL-GEL CLAD FIBEROPTIC SENSORS WITH TIME-RESOLVED DETECTION

Sol-gel clad fiber-optic waveguides are investigated as intrinsic dist ributed fiber-optic chemical sensors. The porous sol-gel cladding allo ws diffusion of analytes into the evanescent held region close to the fiber-optic core. Pulsed optical excitation (0.5 ns) and time-resolved emission detection can be used to simultaneously monitor several mult iplexed sensor clad regions along a single optical fiber. Time-resolve d detection is also demonstrated as a means of resolving both the spat ial location and the fluorescence kinetics of intrinsic sensor chromop hores along the fiber-optic waveguide. Narrowband excitation and spect rally resolved emission provide additional experimental means for disc riminating between specific sensor clad regions. A fluorescein-doped s ilica xerogel clad pH sensor and an undoped aluminosilica xerogel clad quinone sensor are demonstrated as intrinsic sol-gel clad fiber-optic sensors.