Pump-Probe Investigation of Picosecond laser-Gas Target Interactions,

We report on a time-resolved investigation of the hydrodynamics of a laser-produced plasma. A 100 ps pulse is focused into a chamber filled with xenon for various pulse energies and pressures. This pulse the pump pulse forms a plasma, which is probed by a second pulse the probe pulse with a variable delay of up to 2.5 ns. The gradients in the plasma density profile produce a lensing effect on the probe pulse. The beam transmitted through the plasma is viewed with a CCD camera. The diffraction pattern of the probe pulse can be seen by subtracting the image of the first pulse beam from the image produced by the two-pulse beam.