Fiber-optic oxygen sensor using molybdenum chloride cluster luminescence

We report on a reflection-mode fiber-optic oxygen sensor based on the O-3(2 ) quenching of the red emission from hexanuclear molybdenum chloride cluste rs. Measurements of the probe operating in a 0%-21% gaseous oxygen environm ent have been obtained, a range suitable for biological and automotive appl ications. The luminescence signal increases with decreasing oxygen concentr ation in accordance with theory. We observe clearly resolvable steps in the sensor response for changes of 0.1% absolute oxygen concentration in the 0 %-1.0% range. The response time of the fiber probe is theoretically predict ed to be 1 s. (C) 1999 American Institute of Physics. [S0003-6951(99)01445- X].