PICOSECOND SOFT-X-RAY SOURCE FROM SUBPICOSECOND LASER-PRODUCED PLASMAS

Short-pulse high-intensity laser-plasma interactions are investigated experimentally with temporally and spectrally resolved soft-x-ray diag nostics. We demonstrate that, by adjustment of the incident laser flux , the pulse width of the laser-produced x rays emitted from solid targ ets may be varied to as short as the picosecond time scale. Bright, pi cosecond, broadband emission characteristic of a short-scale-length hi gh-density plasma is produced only when a high laser contrast (10(10)) is used. The results are found to be in qualitative agreement with bo th the predictions of a simple model of radiation from a collisionally dominated atomic system and the results obtained from a numerical sim ulation. (C) 1996 Optical Society of America