Recent developments in x-ray laser research at LLE

The authors present results and analysis of recent experiments using multiple-foil target designs for a collisional excitation x-ray laser in Ne-like nickel and germanium. These targets, which are designed to yield higher gains than single-exploding-foil targets, are irradiated by 600 ps pulses of 351 nm light in a single 18-mm line from GDL. The lasing lines at --230 A are observed with a 1-m grazing incidence grating spectrometer. They discuss the relative merit of different pump-laser wavelengths and present experimental results for three wavelengths: 1.06 μm, 527 nm, and 351 nm. They present plans for the conversion of the GDL laser to a --100 J - 10 ps laser (10 TW) which will be used for producing a recombinationally pumped laser in Al which is predicted to lase at 39 A. Results of computer simulation of these proposed experiments are presented