Multicomponent gas analysis with first-overtone CO laser

Abstract

The quantitative analysis of sensitivity and selectivity characteristics for spectroscopic gas detection with different mid-infrared molecular lasers was carried out. In particular, the partial and cross sensitivity, the partial selectivity and total parameter of selectivity and sensitivity for gas detection in gas mixture of seven components with HF, DF and first-overtone (FO) carbon monoxide lasers were calculated. The analysis demonstrated that FO CO laser due to its spectral properties is very perspective source of light for laser spectroscopy of multicomponent gas mixtures. The FO CO laser spectral range (2.5-4.2 microns) overlaps the 'transparency window' of the atmosphere in the wavelength range (~3 - 4 microns) and covers that of HF and DF lasers, with its ro-vibrational line spacing being several times less than that of those lasers. The FO CO laser spectral lines coincide with a large number of absorption lines belonging to numerous organic and non-organic substances which can be found in plasma induced by laser ablation. The linear and nonlinear absorption of the FO CO laser by different gaseous substances was calculated and compared with the experimental data.