Optical and plasma smoothing of laser imprinting in targets driven by lasers with SSD bandwidths up to 1 THz

The creation of a plasma atmosphere in laser-target interactions increases the distance between the regions of laser absorption and hydrodynamic insta bility (ablation front), thus allowing thermal smoothing and a reduction of laser-imprinted modulations that reach the unstable ablation region. The t otal laser imprinting is reduced with pulse shapes that produce a plasma at mosphere more rapidly and by the implementation of temporal beam smoothing. These effects are measured and found to be consistent with models for the hydrodynamics and optical smoothing by spectral dispersion (SSD). Imprintin g is reduced as the laser bandwidth is increased from 0.2 to 1.0 THz. (C) 2 001 American Institute of Physics.