[1] [1] Nagata Y, Midorikawa K, Kubodera S et al.. Soft-X-ray amplification of the lyman-α transition by optical-field-induced ionization. Phys. Rev. Lett., 1993, 71(23):3774～3777

[2] [2] Lemoff B E, Barty C P J, Harris S E. Femtosecond-pulse-driven electron-excited XUV lasers in eight-times-ionized noble gases. Opt. Lett., 1994, 19(8):569～571

[3] [3] Lemoff B E, Yin G Y, GordonⅢ C L et al.. Demonstration of 10-Hz femtosecond-pulse-driven XUV laser at 41.8 nm in Xe Ⅸ. Phys. Rev. Lett., 1995, 74(9):1574～1577

[4] [4] Fill E, Borgstrom S, Larsson J et al.. XUV spectra of optical-field-ionized plasmas. Phys. Rew. (E), 1995, 51(6):6016～6027