Nonstationary Mandelstam-Brillouin stimulated scattering of focused light beams under conditions of saturation

It is shown that with nonstationary Mandelstam-Brillouin stimulated scattering in SF6 (p = 16 atm), wave front reversal occurs over a wide range of changes in the energy of the laser radiation (0.3 to 3 J). The reversal has a large reflectivity (approximately 0.9-0.95) and high precision (approximately 0.95). It is found that the nonstationariness of the Mandelstam-Brillouin scattering leads to time variation in the spatial distribution of the hypersound and laser radiation intensities in the bulk of the nonlinear medium. With a sufficiently high energy of laser radiation, the characteristic region of its attenuation from the scattering by the hypersound into an oncoming Stokes wave is localized near the entrance to the nonlinear medium. As a result, the intensity of the radiation passing through the focal instability decreases sharply, and this aids in eliminating the optical breakdown.