Petawatt laser system and experiments

We have developed a hybrid Ti:sapphire-Nd:glass laser system that produces more than 1.5 PW of peak power. The system has produced up to 680 J of energy on target at 1054 nm in a compressed 440/spl plusmn/20-fs pulse by use of 94-cm diffraction gratings. A focused irradiance of up to 6/spl times/10/sup 20/ W/cm/sup 2/ was achieved using an on-axis parabolic mirror and adaptive optic wavefront control. Experiments with the petawatt laser system focused the beam on solid targets and produced a strongly relativistic interaction. Energy content, spectra, and angular pattern of the photon, electron, and ion radiations were diagnosed in a number of ways, including several nuclear activation techniques. Approximately 40-50% of the laser energy was converted to broadly beamed hot electrons, with an associated bremsstrahlung beam. High luminosity ion beams were observed normal to the rear surface of various targets with energies up to /spl ges/55 MeV, representing /spl sim/7% of the laser energy. These and other results are presented.