Multi-level effects in the high-order harmonic generation driven by intense frequency-comb laser fields*
Zhao Di†, Jiang Chen-Wei, Li Fu-Li
       
The P g → e as a function of Δ ϕ in ec-type three-level systems with ħω gc = 0.23 (solid line) and 0.27 a.u. (dashed line). The peak intensity of the frequency-comb laser field is (a) 1 × 1014 W/cm2 and (b) 1 × 1015 W/cm2. Other parameters used are the same as those in Fig.  2 .