Spectroscopy and Spectral Analysis, Volume. 32, Issue 1, 41(2012)
Off-Axis Cavity Enhanced Absorption Spectroscopy Detection Techniques for the Measurement of Carbon Dioxide
The spectrum of carbon monoxide was obtained around 1.573 μm using a tunable distributed feedback semiconductor laser with a high-finesse cavity at room temperature via off-axis cavity enhanced absorption (CEA) spectroscopic technique. The absorption line of carbon monoxide at 6 357.311 6 cm-1 was chosen for trace detection. Meanwhile, in order to get more accurate measurements, absorption path length of the cavity calibration methods was studied, and a simple and practical calibration method was given. The results show that, the equivalent absorption path length of high-precision optical resonator was ~1 195.73 m. At last, we got the concentration of carbon monoxide in the real atmosphere to be ~388.346 ppm (S/N≈22), and the detection limit of carbon monoxide was 17.65 ppm. By combination of wavelength modulation technology and OA-CEAS technology, a minimum detectable concentration of 0.36 ppm (S/N≈1 064) was achieved eventually.
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ZHAO Hui, WANG Gui-shi, CAI Ting-dong, GAO Xiao-ming. Off-Axis Cavity Enhanced Absorption Spectroscopy Detection Techniques for the Measurement of Carbon Dioxide[J]. Spectroscopy and Spectral Analysis, 2012, 32(1): 41
Received: Mar. 16, 2011
Accepted: --
Published Online: Feb. 20, 2012
The Author Email: Hui ZHAO (zhhui08@mail.ustc.edu.cn)