[1] Sokolov A V,Walker D R,Yavuz D D, et al. Ramam generation by phased and antiphased molecular states.Phys Rev Lett, 2000,85(3):562～565

[2] Antoine P,Huillier A L′,Lewenstein M. Attosecond pulse trains using High-order harmonics. Phys Rev Lett, 1996, 77(7):1234～1237

[3] Antoine P,Milosevic D B,Huillier A L′, et al. Generation of attosecond pulses in macroscopic media.Phys Rev A,1997,56(6):4960～4969

[4] Chang Z, Rundquist A,Wang H, et al. Temporal phase control of soft-x-ray harmonic emission. Phys Rev A, 1998, 58:30～33

[7] Hentslchel M,Kienberger R,Spielmann C,et al.Attosecond metrology. Nature, 2001, 414(29):509～513