Characteristics of the spatial structure selection by focusing with a kinof orm under stimulated Brillouin scattering conditions

An experimental investigation was made of the spatial structure of the radiation generated as a result of stimulated Brillouin scattering of weakly inhomogeneous pump radiation. Focusing of the radiation by a kinoform of the Fresnel lens type widened the range of pump energies in which it was possible to select a component with a smooth wavefront from weakly inhomogeneous radiation. When the direction of propagation of the pump radiation deviated from the Fresnel lens axis, the direction of propagation of the Stokes beam did not reproduce the direction of propagation of the pump radiation: the Stokes component contracted toward the Fresnel lens axis. This effect was observed against the background of strong fluctuations.