Saturation effect for H(2)O absorption lines at ruby laser wavelengths

The dependence of the spectral coefficient of atmospheric water vapor absorption on ruby-laser radiation intensity has been studied experimentally. Measurements were made using an optoacoustic laser spectrometer with a sensitivity of 10(-9) cm(-1) J(-1). The contours of the H(2)O absorption lines at 694.215 nm, 694.238 nm, and 694.38 nm were measured at two different values of radiation intensity within 5-100 MW/cm(2). The values of the saturation parameter were calculated using the observed decrease of absorption in the line maximum; they were 210 +/- 23 MW/cm(2), 140 +/- 15 MW/cm(2), and 180 +/- 20 MW/cm(2) for the 694.215-nm, 694.238-nm, and 694.38-nm, lines, respectively. The values of the absorption parameter are in satisfactory agreement with the calculated results. The dependence of the saturation parameter on pressures between 250-750 Torr was investigated for the isolated 694.38-nm absorption line.