Tabletop transient collisional excitation x-ray lasers

Abstract

Recent transient collisional excitation x-ray laser experiments are reported using the COMET tabletop laser driver at the Lawrence Livermore National Laboratory (LLNL). Ne-like and Ni-like ion x-ray laser schemes have been investigated with a combination of long 600 ps and short {approximately}1 ps high power laser pulses with 5-10 J total energy. We show small signal gain saturation for x-ray lasers when a reflection echelon traveling wave geometry is utilized. A gain length product of 18 has been achieved for the Ni-like Pd 4d{r_arrow}4p J=0-1 line at 147 {angstrom}, with an estimated output of {approximately}10{micro}J. Strong lasing on the 119 {angstrom} Ni-like Sn line has also been observed. To our knowledge this is the first time gain saturation has been achieved on a tabletop laser driven scheme and is the shortest wavelength tabletop x-ray laser demonstrated to date. In addition, we present preliminary results of the characterization of the line focus uniformity for a Ne-like ion scheme using L-shell spectroscopy.