Lasing to ground state of ions in discharge created plasma in microcapillary

The objective of this paper is to present the results of recent experiments on lasing to ground state in H-like LiIII ions in microcapillary plasma. T he experiments were conducted at both Princeton University and NRL. Two met hods were used to fill the microcapillaries with plasma: ablation of microc apillary walls when irradiated with a low power laser beam of a few ns dura tion, or fast electrical discharge. Powerful subpicosecond laser beams (wit h wavelength of 0.25 mum at Princeton University and 1.053 mum at NRL) were used for longitudinal pumping of microcapillary plasma following by the fa st recombination and gain generation in the transition to ground state of h ydrogen-like LiIII ions. In these experiments the dependence of the gain on the specific method of the preplasma creation, electric discharge versus l ow-power laser, pumping laser wavelength (0.248 mum versus 1.053 mum), and the geometry of the experiment (microcapillary dimensions and electrode des ign) were investigated. Results of these investigations are presented and d iscussed with the particular emphasis on the experiments with the lpm subpi cosecond laser pumping of discharge-produced microcapillary plasma.