Macroscopic effects for quantum control of broadband isolated attosecond pulse generation with a two-color field

With a theoretical model including both the single-atom and collective responses to the two-color laser field, we investigate the influence of macroscopic effects on the generation of isolated attosecond pulse. It is shown that broadband supercontinuous high harmonics can be produced by controlling the ionization or acceleration step of high-order harmonic generation (HHG). Utilizing the broadband supercontinuum, isolated sub-100 attosecond pulse can be generated. We also investigate the influence of atomic density on the enhancement of HHG. Moreover, the distortion and dephasing of two-color field in the propagation of ionized gas medium are also discussed.