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An all-optical gas sensor...All terrain !

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An all-optical CO2 sensor based on measuring the absorption of infrared light by the CO2 molecules, was developed and patented by a team of Iramis. The conversion frequency of the absorption signal enables shift the measurement, while remaining insensitive to electromagnetic interference.

A chalcogenide fiber (Ga5Ge20Sb10S65), doped with rare earth ions (dysprosium Dy3 +) and pumped by a fiber laser diode, supplies a signal in the medium infrared, around 4.35 microns. It passes through the cell to analyze where it is absorbed the energy of vibration of the molecules. The outgoing signal is then frequency converted to 800 nm, and then fed into a commercial optical fiber before being measured. Of field tests have demonstrated the performance of the sensor, especially its sensitivity.

These works are the result of collaboration between researchers from the CIMAP / Iramis and the Institute of Chemical Sciences of Rennes.

Contact: Patrice Camy, Alain Braud

Ref. "Mid-IR optical sensor for CO2 detection based on fluorescence absorbance of Dy3 +: Ga5Ge20Sb10S65 fibers" F. Starecki, F. Charpentier, Doualan JL, L. Quetel, K.Michel, R. Chahal, J. Troles, B. Office Braud A., P. Camy, V. Nazabal, Sensors and Actuators.