Investigation of nonlinear absorption in H2O vapors subjected to strong optical fields with linear and circular polarizations

The optoacoustic method was used to investigate the change in the collisional profile of the 694.38 nm absorption line of H₂O subjected to strong fields of laser radiations with linear and circular polarizations. The measurements were carried out with a resolution of 0.015 cm^–1 using laser radiations of intensities up to 50 MW/cm². The study of nonlinear absorption was made for H₂O–air, H₂O–N₂, H₂O–Ar, and H₂O–Xe mixtures at total pressures in excess of 180 Torr using radiations of several intensities.