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Low-cost resonant cavity Raman gas probe for multi-gas detection


Raman based gas sensing can be attractive in several industrial applications, due to its multi-gas sensing capabilities and its ability to detect
O2 and N2. In this article, we have built a Raman gas probe, based on low-cost components, which has shown an estimated detection limit
of 0.5 % for 30 second measurements of N2 and O2. While this detection limit is higher than that of commercially available equipment, our
estimated component cost is approximately one tenth of the price of commercially available equipment. The use of a resonant Fabry-Pérot
cavity increases the scattered signal, and hence the sensitivity, by a factor of 50. The cavity is kept in resonance using a piezo-actuated
mirror and a photodiode in a feedback loop.
The system described in this article was made with minimum-cost components to demonstrate the low-cost principle. However, it is
possible to decrease the detection limit using a higher-powered (but still low-cost) laser and improving the collection optics. By applying
these improvements, the detection limit and estimated measurement precision will be sufficient for e.g. the monitoring of input gases in
combustion processes, such as e.g. (bio-)gas power plants. In these processes, knowledge about gas compositions with 0.1 % (absolute)
precision can help regulate and optimize process conditions.
The system has the potential to provide a low-cost, industrial Raman sensor that is optimized for specific gas-detection applications.


Academic article




  • SINTEF Digital / Smart Sensor Systems



Published in

Journal of the European Optical Society - Rapid Publications





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