SBS REFLECTIVITY FROM SPATIALLY SMOOTHED LASER-BEAMS - RANDOM-PHASE PLATES VERSUS POLARIZATION SMOOTHING

The reflectivity due to stimulated Brillouin backscattering (SBS) from an ensemble of independent laser speckles is investigated for differe nt speckle statistics. Calculations are based on numerical simulations with a multidimensional code and a compact model describing the main features of speckle self-focusing, In particular, the simulations and the model are applied to speckle ensembles due to the random phase pla te (RPP) and polarization smoothing (PS) techniques. A stronger SBS in hibition for PS with respect to the RPP technique is demonstrated. (C) 1998 American Institute of Physics. [S1070-664X(98)01107-0].