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dc.contributor.authorYu, Yajun
Sanchez, Nancy P.
Lou, Minhan
Zheng, Chuantao
Wu, Hongpeng
Głuszek, Aleksander K.
Hudzikowski, Arkadiusz J.
Griffin, Robert J.
Tittel, Frank K.
dc.date.accessioned 2017-02-08T16:34:32Z
dc.date.available 2017-02-08T16:34:32Z
dc.date.issued 2017
dc.identifier.citation Yu, Yajun, Sanchez, Nancy P., Lou, Minhan, et al.. "CW DFB-QCL and EC-QCL based sensor for simultaneous NO and NO2 measurements via frequency modulation multiplexing using multi-pass absorption spectroscopy." Proceedings of SPIE, 10111, (2017) SPIE: http://dx.doi.org/10.1117/12.2251228.
dc.identifier.urihttps://hdl.handle.net/1911/93857
dc.description.abstract Nitrogen oxides (NOx), including nitric oxide (NO) and nitrogen dioxide (NO2) play important roles in determining the photochemistry of the ambient atmosphere, controlling the production of tropospheric ozone, affecting the concentration levels of the hydroxyl radical, and forming acid precipitation. A sensor system capable of simultaneous measurements of NO and NO2 by using a commercial 76 m astigmatic multi-pass gas cell (MPGC) was developed in order to enable fast-response NOx detection. A continuous wave (CW), distributed-feedback (DFB) quantum cascade laser (QCL) and a CW external-cavity (EC) QCL were employed for targeting a NO absorption doublet at 1900.075 cm-1 and a NO2 absorption line at 1630.33 cm-1, respectively. Both laser beams were combined and transmitted through the MPGC in an identical optical path and subsequently detected by a single mid-infrared detector. A frequency modulation multiplexing scheme was implemented by modulating the DFB-QCL and EC-QCL at different frequencies and demodulating the detector signal with two Labview software based lock-in amplifiers to extract the corresponding second-harmonic (2f) components. Continuous monitoring of NO and NO2 concentration levels was achieved by locking the laser frequencies to the selected absorption lines utilizing a reference cell filled with high concentrations of NO and NO2. The experimental results indicate minor performance degradation associated with frequency modulation multiplexing and no cross talk between the two multiplexed detection channels. The performance of the reported sensor system was evaluated for real time, sensitive and precise detection of NO and NO2 simultaneously.
dc.language.iso eng
dc.publisher SPIE
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
dc.title CW DFB-QCL and EC-QCL based sensor for simultaneous NO and NO2 measurements via frequency modulation multiplexing using multi-pass absorption spectroscopy
dc.type Journal article
dc.citation.journalTitle Proceedings of SPIE
dc.subject.keywordquantum cascade laser
nitric oxide
nitrogen dioxide
multi-pass absorption
wavelength modulation spectroscopy
frequency modulation multiplexing
trace gas detection
laser sensors
dc.citation.volumeNumber 10111
dc.type.dcmi Text
dc.identifier.doihttp://dx.doi.org/10.1117/12.2251228
dc.type.publication publisher version
dc.citation.articleNumber 1011108


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