High Sensitive Detection of Carbon Monoxide Based on Novel MultiPass Cell

Hua, 夏滑 Xia; Fengzhong, 董凤忠 Dong; Guojie, 涂郭结 Tu; Bian, 吴边 Wu; Zhirong, 张志荣 Zhang; Yu, 王煜 Wang

doi:10.3788/aos20103009.2596

Cited by 5 publications

(1 citation statement)

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“…The lasers are scanned and the absorption lines selected by a sawtooth signal at the same frequency of 10 Hz, V pp = 600 mV and modulated by a sinusoidal signal at high frequency f 1 = 10 KHz, V pp = 105 mV for the H 2 S laser and f 2 = 20 KHz, V pp = 178 mV for the HCl laser, emitted from homemade digital-control modules [9] (which contain signal generator, digital lockin amplifier and preliminary processing memory). Also, this project relied on a 2-in-1 coupler and injected into a single-mode optical fiber to deliver the combined laser beams to a new-style multiple-pass cell [10,11]. Output absorption components from the same detector are transmitted into a set of digital-control modules to obtain the corresponding harmonic signals.…”

Section: The Absorption Spectroscopymentioning

confidence: 99%

Simultaneous detection of multiple gas concentrations with multi-frequency wavelength modulation spectroscopy

Zhang¹,

Xia²,

Dong³

et al. 2013

EPL

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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.

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Section: The Absorption Spectroscopymentioning

confidence: 99%