Measurement of trace gases by diode laser cavity ringdown spectroscopy

1999 ◽  
Author(s):  
Daniele Romanini ◽  
Alexander A. Kachanov ◽  
Jerome Morville ◽  
Marc Chenevier
Keyword(s):  
Diode Laser ◽  
Trace Gases ◽  
Laser Cavity ◽  
Cavity Ringdown Spectroscopy ◽  
Cavity Ringdown

scholarly journals A Wide-Range and Calibration-Free Spectrometer Which Combines Wavelength Modulation and Direct Absorption Spectroscopy with Cavity Ringdown Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 585 ◽  
Author(s):  
Zhen Wang ◽  
Yanjun Du ◽  
Yanjun Ding ◽  
Zhimin Peng
Keyword(s):  
Diode Laser ◽  
Tunable Diode Laser ◽  
Cavity Ringdown Spectroscopy ◽  
Wavelength Modulation ◽  
Direct Absorption ◽  
Cavity Ringdown ◽  
Direct Absorption Spectroscopy ◽  
Ringdown Time ◽  
Wide Range ◽  
Calibration Free

A wide-range, calibration-free tunable diode laser spectrometer is established by combining wavelength modulation and direct absorption spectroscopy (WM-DAS) with continuous wave cavity ringdown spectroscopy (CW-CRDS). This spectrometer combines the benefits of absolute concentration measurements, wide range, and high speed, using WM-DAS with enhanced noise reduction in CW-CRDS. The accurate baseline ringdown time, τ0, is calculated by the absorption peak (measured by WM-DAS) and the ringdown time containing gas absorption information (measured by CW-CRDS at the center wavelength of the spectral line). The gas concentration is obtained without measuring τ0 in real time, thus, greatly improving the measuring speed. A WM-DAS/CW-CRDS spectrometer at 1.57 μm for CO detection was assembled for experimental validation of the multiplexing scheme over a concentration ranging from 4 ppm to 1.09% (0.1 MPa, 298 K). The measured concentration of CO at 6374.406 cm−1 shows that the dynamic range of this tunable diode laser absorption spectrometer is extendable up to five orders of magnitude and the corresponding precision is improved. The measurement speed of this spectrometer can extend up to 10 ms, and the detection limit can reach 35 ppb within 25 s.

Multiplexed continuous-wave diode-laser cavity ringdown measurements of multiple species

2000 ◽  
Vol 39 (12) ◽  
pp. 2009 ◽  
Author(s):  
Gerhard Totschnig ◽  
Douglas S. Baer ◽  
Jian Wang ◽  
Franz Winter ◽  
Hermann Hofbauer ◽  
...  
Keyword(s):  
Diode Laser ◽  
Continuous Wave ◽  
Laser Cavity ◽  
Cavity Ringdown ◽  
Multiple Species
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