Photonic Sensors, Volume. 5, Issue 2, 109(2015)
Ammonia Sensing System Based on Wavelength Modulation Spectroscopy
A sensing system in the near infrared region has been developed for ammonia sensing based on the wavelength modulation spectroscopy (WMS) principle. The WMS is a rather sensitive technique for detecting atomic/molecular species, presenting the advantage that it can be used in the near-infrared region by using the optical telecommunications technology. In this technique, the laser wavelength and intensity were modulated by applying a sine wave signal through the injection current, which allowed the shift of the detection bandwidth to higher frequencies where laser intensity noise was typically lower. Two multi-pass cells based on free space light propagation with 160 cm and 16 cm of optical path length were used, allowing the redundancy operation and technology validation. This system used a diode laser with an emission wavelength at 1512.21 nm, where NH3 has a strong absorption line. The control of the NH3 gas sensing system, as well as acquisition, processing and data presentation was performed.
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Duarte VIVEIROS, Joao FERREIRA, Susana O. SILVA, Joana RIBEIRO, Deolinda FLORES, Jose L. SANTOS, Orlando FRAZAO, and Jose M. BAPTISTA. Ammonia Sensing System Based on Wavelength Modulation Spectroscopy[J]. Photonic Sensors, 2015, 5(2): 109
Category: Regular
Received: Jan. 20, 2015
Accepted: Mar. 16, 2015
Published Online: Apr. 20, 2015
The Author Email: VIVEIROS Duarte (carlos.d.viveiros@inescporto.pt)