Blue LED Excitation Research Articles

LED-based fibre optic oxygen sensor using sol-gel coating

An intrinsic evanescent wave fibre optic sensor for oxygen is reported. The sensor is based on the quenching of fluorescence from a ruthenium complex trapped in the cage-like structure of a sol-gel-derived porous film on a de-clad section of multimode optical fibre. The sensor exhibits excellent performance using blue LED excitation and silicon photodiode detection, and establishes the viability of low-cost portable sensor devices based on the sol-gel process. Gas phase measurement data over the range 0–100% oxygen exhibit high signal-to-noise ratio (~150), good repeatability and short response time (< 5 s).