Effect of laser linewidth on the tunable diode laser absorption spectroscopy system

Abstract In this paper, a theoretical investigation of the influence of laser linewidth on the tunable diode laser absorption spectroscopy system is presented. The theoretical analysis and formula discussion of laser line shape are carried out by frequency noise spectrum density. Taking Lorentz line shape of laser line width as an example, the interaction principle of laser line width and gas absorption spectral line is analyzed. The relation curve of laser linewidth and maximum amplitude is simulated by MATLAB platform with self-defined simulation parameters. These results can provide theoretical basis for guiding the selection of laser and gas absorption spectral line and improving the detection accuracy of gas concentration.