B. Rus et al., OBSERVATION OF INTENSE SOFT-X-RAY LASING AT THE J = 0 TO J = 1 TRANSITION IN NEON-LIKE ZINC, Journal of the Optical Society of America. B, Optical physics, 11(4), 1994, pp. 564-573
We present experimental results from recent studies of soft-x-ray lasi
ng in Ne-like Zn (Z = 30). The lasing plasma was produced by irradiati
on of slab targets as much as 2 cm long with intensities of approximat
ely 1.4 x 10(13) W cm-2 at lambda = 1.06 mum in pulses of 600 ps (FWHM
). Amplification at three 3p-3s transitions was observed. While the J
= 2 to J = 1 transitions at 262 and 267 angstrom provided gain coeffic
ients of 2.3 and 2.6 cm-1, respectively, the J = 0 to J = 1 transition
at 212 angstrom exhibited a significantly larger gain of 4.9 cm-1 and
yielded a much brighter signal. Furthermore, its temporal characteris
tics were revealed to be unlike those of the J = 2 to J = 1 transition
s. The results indicate that the J = 0 to J = 1 line originates from a
different plasma region than do the J = 2 to J = 1 lines and that the
temporal evolution of the pumping process into its upper lasing level
J = 0 differs considerably from that to the J = 2 levels. In addition
, the gain and the gain-length product of approximately 10 achieved in
this experiment are, to our knowledge, the highest ever reported for
a driving laser of similar energy (approximately 450 J).