Abstract
A multi-frequency wavelength modulation spectroscopy (MF-WMS) method for simultaneous monitoring multiple gas concentrations is reported. Two wavelength lasers are selected and scanned at the same sawtooth waveform and different sinusoidal modulation frequencies. Also, a 2-in-1 coupler is used to collect laser beams into a single-mode fiber to deliver the combined beams to a same optical path. The outputs from the same InGaAs detector are demodulated by a set of homemade digital lock-in-amplifiers to obtain the harmonic signals, accordingly. The new multi-pass cell was designed and filled with five different concentrations of H2S and HCl gas mixtures for further analysis. In addition, an digital filter and a data running means method were used to further improve the stability. The results show that the signal-to-noise ratio and the anti-interference ability had been improved and the MF-WMS system gives a good performance in terms of reproducibility and feasibility.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
