Relativistic accelerations in femtosecond laser-produced plasmas

Summary form only given. The interaction of femtosecond laser pulses with solids at high intensities leads to the formation of high-density plasmas with high electron densities. It is well known that frequency-resolved measurements of reflected laser light from a plasma surface reveal the mass motion driven by the heating laser pulse. A more complete picture of the plasma motion can be obtained by measuring the phase and amplitude of the reflected pulse. Frequency-resolved optical gating (FROG) detection is a method that provides a two-dimensional temporally resolved spectrum from which phase and amplitude information can be retrieved. We have used this technique, to our knowledge for the first time, to measure the reflected waveform in a high-intensity laser-solid interaction experiment.