[1] Protopapas M, Keitel C H, Knight P L. Atomic physics with super-high intensity lasers. Rep. Prog. Phys., 1997, 60:389～486

[2] Watson J B, Sanpera A, Chen X et al.. Harmonic generation from a coherent superposition of states. Phys. Rev. (A), 1996, 53(4):R1962～R1965

[3] de Morrison Faria C F, Drr M, Sandner W. Importance of excited bound states in harmonic generation. Phys. Rev. (A), 1998, 58(4):2990～2999

[4] Hu S X, Xu Z Z. Enhanced harmonic emission from ionized clusters in intense laser pulses. Appl. Phys. Lett., 1997, 71(18):2605～2607

[5] Gauthey F I, Keitel C H, Knight P L. et al. Phase of harmonics from strongly driven two-level atoms. Phys. Rev. (A), 1997, 55(1):615～621

[6] Taeb R, Véniard V, Maquet A. Theory of two-color pump-probe determination of ionization dynamics. Phys. Rev. (A), 1998, 57(6):R4098～R4101

[7] Kien F L, Midorikawa K, Suda A. Atto-second pulse generation using high harmonics in the multi-cycle regime of the driver pulse. Phys. Rev. (A), 1998, 58(4):3311～3319

[8] Krause J L, Schafer K J, Kulander K C.High order harmonic generation from atoms and ions in the high intensity regime. Phys. Rev. Lett., 1992, 68(24):3535～3538

[9] Corkum P B. Plasma perspective on strong-field multi-photon ionization. Phys. Rev. Lett., 1993, 71(13):1994～1997

[10] Schafer K J, Yang B R, Dimauro L F et al.. Above threshold ionization beyond the high harmonic cutoff. Phys. Rev. Lett., 1993, 70(11):1599～1602

[11] Protopapas M, Lappas D G, Keitel C H et al.. Re-collision, bremsstrahlung, and atto-second pulse from intense laser fields. Phys. Rev. (A), 1996, 53(5):R2933～R2936

[12] Zuo T, Bandrauk A D. Control of high-order harmonic generation in strong laser fields. Phys. Rev. (A), 1995, 51(5):3991～3998

[15] Krause J L, Schafer K J, Kulander K C. Calculation of photo-emission from atoms subject to intense laser fields. Phys. Rev. (A), 1992, 45(7):4998～5010

[16] Eberly J H, Su Q, Javanainen J. Nonlinear light scattering accompanying multi-photon ionization. Phys. Rev. Lett., 1989, 62(8):881～884