Reduction of laser self-focusing in plasma by polarization smoothing

Dramatic reductions in the filamentation of an intense speckled laser beam in a hot, high-density plasma are reported in simulations of polarization smoothing (PS), which consists of irradiating the plasma with two superimposed, orthogonally polarized and uncorrelated speckle patterns. PS instantaneously smooths the spatial beam structure, and thus can be more effective than temporal smoothing techniques. Even greater reduction in filamentation, offering improved prospects for inertial fusion, results from combining these two methods. (C) 1998 American Institute of Physics. [S1070-664X(98)00607-7].