LIGHT-EMITTING-DIODE-BASED OXYGEN SENSING USING EVANESCENT-WAVE EXCITATION OF A DYE-DOPED SOL-GEL COATING

Two evanescent wave fiber optic sensors for oxygen are reported: one i ntensity based and the other based on phase fluorimetry. Both sensors employ the quenching by oxygen of the fluorescence from a ruthenium co mplex trapped in the cagelike structure of a set-gel-derived porous fi lm on a declad section of multimode optical fiber. The sensors exhibit excellent performance using excitation from new high brightness blue LEDs and establish the viability of low-cost portable sensor devices b ased on the sol-gel process.