HELIUM-LIKE RECOMBINATION PUMPED SOFT-X-RAY LASERS

Experimental studies on recombination pumped soft x-ray lasers with he lium-like ions are presented. The four-beam multi-TW neodymium-doped p hosphate glass laser system at the Institute for Solid State Physics o f the University of Tokyo was used in this work, From simultaneous tim e- and space-resolved spectra of the resonance lines of helium-like al uminium ions, population inversions between the n = 3 and 2 levels wer e observed. Details on the first observation of amplification in a rec ombination-pumped helium-like soft x-ray laser, exhibiting a time-reso lved small-signal gain of 3.3 +/- 0.5 cm(-1) for the 3 D-1-2 P-1 trans ition of helium-like nitrogen, are also given.