scholarly journals Measurements of N2, CO2, Ar, O2 and Air Pressure Broadening Coefficients of the HCl P(5) Line in the 1–0 Band Using an Interband Cascade Laser

2021 ◽  
Vol 11 (11) ◽  
pp. 5190
Author(s):  
Zhechao Qu ◽  
Javis A. Nwaboh ◽  
Gang Li ◽  
Olav Werhahn ◽  
Volker Ebert
Keyword(s):  
Absorption Line ◽  
Pressure Range ◽  
Air Pressure ◽  
Tunable Diode Laser ◽  
Pressure Broadening ◽  
Laser Absorption ◽  
Interband Cascade Laser ◽  
First Time ◽  
Diode Laser Absorption ◽  
Metrological Approach

We determine the CO2, N2, Ar, O2 and air pressure broadening coefficients of the H35Cl P(5) absorption line at 2775.77 cm−1 in the fundamental (1←0) band using a newly developed direct tunable diode laser absorption spectroscopy (dTDLAS)-based spectrometer employing a mid-IR interband cascade laser (ICL). For the first time, a reliable and consistent set of five different foreign pressure broadening coefficients for the same HCl P(5) line has been measured by a consistent metrological approach covering pressures from 100 to 600 hPa at temperatures of 294 and 295 K. The relative uncertainties of the stated CO2, N2, Ar, O2 and Air pressure broadening coefficients are in 1–3% range. The results are compared to previously available literature data—two broadening coefficients have been improved in accuracy and two have been determined for the first time in the sub 1000 hPa pressure range.

scholarly journals A Trace C2H2 Sensor Based on an Absorption Spectrum Technique Using a Mid-Infrared Interband Cascade Laser

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 530 ◽  
Author(s):  
Ye Mu ◽  
Tianli Hu ◽  
He Gong ◽  
Ruiwen Ni ◽  
Shijun Li
Keyword(s):  
Absorption Spectroscopy ◽  
Second Harmonic ◽  
Harmonic Signal ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Integration Time ◽  
Detection Accuracy ◽  
Laser Absorption ◽  
Interband Cascade Laser ◽  
Diode Laser Absorption

In this study, tunable diode laser absorption spectroscopy (TDLAS) combined with wavelength modulation spectroscopy (WMS) was used to develop a trace C2H2 sensor based on the principle of gas absorption spectroscopy. The core of this sensor is an interband cascade laser that releases wavelength locks to the best absorption line of C2H2 at 3305 cm−1 (3026 nm) using a driving current and a working temperature control. As the detected result was influenced by 1/f noise caused by the laser or external environmental factors, the TDLAS-WMS technology was used to suppress the 1/f noise effectively, to obtain a better minimum detection limit (MDL) performance. The experimental results using C2H2 gas with five different concentrations show a good linear relationship between the peak value of the second harmonic signal and the gas concentration, with a linearity of 0.9987 and detection accuracy of 0.4%. In total, 1 ppmv of C2H2 gas sample was used for a 2 h observation experiment. The data show that the MDL is low as 1 ppbv at an integration time of 63 s. In addition, the sensor can be realized by changing the wavelength of the laser to detect a variety of gases, which shows the flexibility and practicability of the proposed sensor.

Tunable Diode Laser Absorption Spectroscopy of the Pyrolysis of Methylsilazane

1991 ◽  
Vol 250 ◽  
Author(s):  
H. C. Sun ◽  
Y. W. Bae ◽  
E. A. Whittaker ◽  
B. Gallois
Keyword(s):  
Absorption Line ◽  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Chemical Vapor ◽  
Decomposition Temperature ◽  
Tunable Diode Laser ◽  
Bond Rupture ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Diode Laser Absorption

AbstractAn understanding of the chemical processes occurring in the gas phase during metalorganic chemical vapor deposition is needed to design novel precursors and for the subsequent control of the composition and the microstructure of the solid product. Tunable diode laser absorption spectroscopy provides a means to precisely monitor specific bond rupture in the precursor during pyrolysis. Methylsilazane [CH3SiHNH]n,, a precursor to silicon-based ceramic thin films, was used to investigate the potential of this technique. Below the decomposition temperature, the intensity of the absorption line at 871.6±0.1 cm−1 corresponding to one of the harmonics from Si-CH3, increased linearly with the vapor pressure of methylsilazane up to 800 Pa and then decreased exponentially. The typical linewidths of the absorption line was approximately 0.006 cm−;1, orders of magnitude narrower than would be observable using conventional infrared techniques. The absorption line was detectable over a pressure range from less than 1 Pa to 10 kPa.

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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