Spatially resolved soft x-ray spectroscopy of femtosecond-laser-induced plasmas

摘要

Time-integrated spatially resolved emission spectra of soft x-rays were obtained in the case of 100-fs-laser irradiation of tantalum and aluminum targets by controlling the time intervals between the main pulse and artificial pre-pulse. The intensities of the main pulse and pre-pulse were fixed to 1.3 x 10~(16) and 2.0 x 10~(14) W/cm~2. X-ray intensities were enhanced more than several ten fold at the optimal pulse-separation time of 2 ns. We confirmed that the main emission area for each target was less than 50-μm long from the target surface. In contrast to the small size of main emission area, we observed that line emissions from the aluminum target expanded far from the target.