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