Reduction of laser imprinting using polarization smoothing on a solid-state fusion laser

We demonstrate a laser beam-smoothing technique known as polarization smoot hing. A birefringent optical wedge splits the individual laser beams into t wo orthogonally polarized beams that, when coupled with a distributed phase plate, produce two speckle patterns shifted with respect to one another. T his instantaneously reduces the on-target nonuniformity by a factor of root 2. We measured this reduction optically and its effect is demonstrated in laser-driven targets. (C) 1999 American Institute of Physics. [S0021-8979(9 9)06407-5].