Diagnostics of water-containing gas mixtures using thermal laser-induced gratings

Temporal profiles of LIG signals recorded at various conditions of gas mixtures employed have been analysed in frame of a model of a two- or three-stage R-T, V-V′, and V-T collisional relaxation of H2O and buffer gas molecules. The informative parameters, like adiabatic sound velocity, gas temperature, H2O mole fraction have been derived. The results of the analysis are presented, demonstrating possibilities and challenges of the technique in application to gas diagnostics.