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Laser frequency shifts in picosecond laser-produced plasmas

The evolution of density profiles in picosecond laser plasmas have been inferred from frequency shifts of reflected probe laser beams. The frequency shifts are caused by two mechanisms: hydrodynamic expansion and ionization front motion. Both time-resolved expansion velocities and ionization rates are presented for plasmas produced by 1 0 Wcm2, 1 ps, 580 nm laser irradiation.