scholarly journals Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Javis Anyangwe Nwaboh ◽  
Thibault Desbois ◽  
Daniele Romanini ◽  
Detlef Schiel ◽  
Olav Werhahn
Keyword(s):  
Absorption Spectroscopy ◽  
Gas Analysis ◽  
Tunable Diode Laser ◽  
Spectroscopic Techniques ◽  
Laser Absorption Spectroscopy ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Fraction Measurement ◽  
Laser Spectroscopic ◽  
Diode Laser Absorption

We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM) method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS), quantum cascade laser absorption spectroscopy (QCLAS), and cavity ring down spectroscopy (CRDS), all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

Measurements of SiH3 and SiH2 Radical Densities in RF Silane Plasmas Using Laser Spectroscopic Techniques

1993 ◽  
Vol 297 ◽  
Author(s):  
T. Goto
Keyword(s):  
Absorption Spectroscopy ◽  
Spectroscopic Techniques ◽  
Laser Absorption Spectroscopy ◽  
Silicon Thin Film ◽  
Laser Absorption ◽  
Intracavity Laser ◽  
Laser Spectroscopic ◽  
Hydrogenated Amorphous ◽  
Diode Laser Absorption ◽  
Silane Plasma

In the RF (13.56 MHz) silane plasma, recently the SiH3 radical density was measured using infrared diode laser absorption spectroscopy, and the correlation between the SiH3 radical density and the growth rate of hydrogenated amorphous silicon thin film was investigated. The SiH2 radical density was also measured using modified laser induced fluorescence spectroscopy and intracavity laser absorption spectroscopy. Those measurement methods and main results are reviewed here.

A Fire Warning Method Using Tunable Diode Laser Absorption Spectroscopy

2021 ◽  
Vol 16 (2) ◽  
pp. 222-229
Author(s):  
Lin Feng ◽  
Jian Wang ◽  
Chao Ding
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Gas Concentration ◽  
Laser Absorption ◽  
Output Wavelength ◽  
Light Beams ◽  
Diode Laser Absorption

Tunable diode laser absorption spectroscopy (TDLAS) technology is adopted herein to detect fire gas produced in the early stage of the fire. Based on this technology, a fire warning detection system with multiple lasers and detectors is proposed. Multiple drivers input laser’s temperature and injected current data, making its output wavelength consistent with the measured gas’ absorption peak wavelengths in absorption spectroscopy. Multiple light beams are coupled to the same optical fiber. After the light beams pass through the long optical path absorption cell filled with fire gas, the beams are separated by a converter. The signals are demodulated by different detectors and further analyzed for fire warnings. After the fire warning system’s design, the system’s various hardware modules are designed, including the light source module, TDLAS controller, gas chamber module, photoelectric detector, and data collection. When the temperature remains unchanged, the output wavelength is linearly related to the injected current. When the injected current remains unchanged, the output wavelength is linearly related to the operating temperature. With a semiconductor laser’s injected current of 40 mA, the initial temperature of 38.6 °C, and the output wavelength of 1578.16 nm, the output wavelength increases continuously as the temperature increases. The harmonic signal amplitude after gas absorption is positively correlated with the measured gas concentration, indicating that the second harmonic signals can estimate the fire gas concentration.

Time-resolved tunable diode laser absorption spectroscopy of pulsed plasma

2013 ◽  
Vol 38 (14) ◽  
pp. 2428 ◽  
Author(s):  
P. Adámek ◽  
J. Olejníček ◽  
M. Čada ◽  
Š. Kment ◽  
Z. Hubička
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Tunable Diode Laser ◽  
Pulsed Plasma ◽  
Laser Absorption Spectroscopy ◽  
Time Resolved ◽  
Laser Absorption ◽  
Diode Laser Absorption
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