High sensitive translational temperature measurement using characteristic curve of second harmonic signal in wavelength modulation spectroscopy

2017 ◽  
Vol 88 (1) ◽  
pp. 013105 ◽  
Author(s):  
Makoto Matsui ◽  
Tohru Yamada
Keyword(s):  
Temperature Measurement ◽  
Second Harmonic ◽  
Characteristic Curve ◽  
Harmonic Signal ◽  
Wavelength Modulation Spectroscopy ◽  
Wavelength Modulation ◽  
Modulation Spectroscopy ◽  
Translational Temperature ◽  
Second Harmonic Signal

scholarly journals A new line-shape asymmetry model for wavelength modulation spectroscopy in gaseous flows

2018 ◽  
Vol 18 (4) ◽  
pp. 158-161 ◽  
Author(s):  
Václav Nevrlý ◽  
Vít Klečka ◽  
Michal Vašinek ◽  
Václav Válek ◽  
Jan Suchánek ◽  
...  
Keyword(s):  
Line Shape ◽  
Second Harmonic ◽  
Differential Evolution Algorithm ◽  
Wavelength Modulation Spectroscopy ◽  
Least Square ◽  
Wavelength Modulation ◽  
Modulation Spectroscopy ◽  
Shape Fitting ◽  
Fitting Procedure ◽  
Automated Line

Abstract This communication reports technical notes on the development and application of an automated line-shape fitting procedure for wavelength modulation spectroscopy (WMS). Near-infrared transitions of carbon dioxide (CO2) around 1573 nm were measured in vertical cold (nonreacting) flow of CO2 at atmospheric pressure using WMS with demodulation at second harmonic frequency. Semi-empirical model based on the set of so-called Gabor functions was developed and parameters of Lorentzian line-shape profile and its asymmetry resulting from simultaneous frequency and amplitude response of the current-modulated semiconductor laser were determined. Nonlinear least-square fitting procedure employing differential evolution algorithm was successfully utilized for performing this task. Line-shape fitting procedure enabling efficient signal de-noising and background subtraction of wavelength modulation spectra was implemented into an open-source code.

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