TY  - JOUR
A1  - Zakrevskyy, Y.
A1  - Ritschel, T.
A1  - Dosche, C.
A1  - Löhmannsröben, Hans-Gerd
T1  - Quantitative calibration - and reference-free wavelength modulation spectroscopy
JF  - Infrared physics & technology
N2  - A unified model for quantitative description of harmonic spectra of gases obtained by wavelength modulation spectroscopy (WMS) technique is presented. In the model, both intensity modulation (IM) and frequency modulation (FM) of the laser emission are taken into account using minimum number of parameters. For the first time, the static behavior of a laser is described as a limiting case of its dynamic response. Laser and its driver are considered as a single device converting applied bias to laser emission. This allows application of the model to any type of laser and the introduced parameters can be assigned to the corresponding laser and/or driver properties. The approach was tested using a distributed feedback (DFB) laser spectrometer. Correctness of the proposed model is justified by very good agreement between the measured and modeled/fitted spectra, which allowed evaluation of the setup performance and assessment of modulation parameters of the DFB laser. An algorithm to minimize the time of numerical calculation of harmonic spectra using numerically approximated Voigt lineshape function was developed. Absolute values of the absorption line parameters (line strength and line width) were obtained from a single calibration- and reference-free spectrum scan with accuracy better than 0.1%.
KW  - Wavelength modulation gas spectroscopy
KW  - Diode laser
KW  - Isotope detection
Y1  - 2012
U6  - https://doi.org/10.1016/j.infrared.2011.12.001
SN  - 1350-4495
VL  - 55
IS  - 2-3
SP  - 183
EP  - 190
PB  - Elsevier
CY  - Amsterdam
ER  -