Experiments to demonstrate the effects of various
beam-smoothing techniques have been performed on the 60-beam,
30-kJ UV OMEGA laser system. These include direct measurements
of the effect beam-smoothing techniques have on laser beam
nonuniformity and on both planar and spherical targets.
Demonstrated techniques include polarization smoothing
and “dual-tripler” third-harmonic generation
required for future broad bandwidth (∼1 THz) smoothing
by spectral dispersion (SSD). The effects of improvements
in single-beam uniformity are clearly seen in the target-physics
experiments, which also show the effect of the laser pulse
shape on the efficacy of SSD smoothing. Saturation of the
Rayleigh-Taylor (RT) growth of the broad-bandwidth features,
in agreement with the Haan model (Haan, 1989), produced
by laser imprinting has also been observed.