Optical fiber probes for fluorescence based oxygen sensing

An optical fiber sensing system, for monitoring oxygen aiming in vivo nuclear magnetic resonance (NMR) applications is presented. Oxygen detection is based on the dynamic quenching of the fluorescence of a ruthenium complex trapped in the porous structure of a sol-gel silica film. Oxygen concentration is determined by phase-modulation fluorometry. Preliminary results concerning the characterization of doped sol-gel thin films deposited by dip coating in glass slides and in optical fiber probes are presented. Four different probe configurations are tested and compared. Best results are obtained with a fiber taper configuration which shows reproducibility and best excitation efficiency. This structure is fully characterized and some considerations regarding optimal fiber optical sensing probes for 02 detection are addressed. (C) 2004 Elsevier B.V. All rights reserved.