Studies of a sulfur capillary discharge irradiated by a ps-laser pulse: a new way towards collisionally pumped table-top X-ray lasers

Results of measurements on a plasma created by a discharge in a sulfur capillary and irradiated by a picosecond laser pulse are presented. Time-resolved transmission measurements and the corresponding XUV spectra are discussed. It is found that the transmission of the laser through the capillary decreases abruptly after the peak of the discharge current, and that the profile of the output laser beam is symmetrised before the onset of the opaque period. The spectra are evidently affected by the laser pulse and show significant intensification on the 3p-3s transition in Ne-like sulfur at 60.84 nm. This observation, combined with the fact that the emission of this line appears spatially displaced from all other lines in the detector and presents a lower divergence, suggest that lasing is occurring.