SOFT-X-RAY LASING TO THE GROUND-STATES IN LOW-CHARGED OXYGEN IONS

Optimal schemes for the creation of a transient population inversion between the ground and excited states of an ion in a subpicosecond-pulse laser-produced plasma are discussed. First results on experimental investigations of possible amplification in the soft-x-ray spectral region on transitions to the ground states in O II, O III, C III, and N III ions are reported. Ions are produced due to optical field ionization of O-2, CO2, and N-2 gases in an intense Ti:sapphire laser field. Amplification on the 2p3s(P-3)-2p(2)(P-3) transition (lambda = 374.12 Angstrom) in O III ions and on the 2p(2)3s(P-2)-2p(3)(D-2) transition (lambda = 616.56 Angstrom) in O II ions has been observed.