High intensity supercontinuum in the plateau region of high-order harmonic generated by a phase delayed two-color laser field

We theoretically demonstrate that an intense supercontinuum can be generated in the high-order harmonic plateau region by using a two-color laser field with appropriate electric intensity and phase delay. By using the semi-classic three-step model and the method of time–frequency analysis, it is proved that both the electric intensity and phase delay of the two-color field are important for the effective generation of smooth supercontinuum in the plateau region. As a case study, we show that an isolated 41 as pulse without phase compensation can be generated directly from the contribution of plateau region alone. These results are benefit for the final obtainment of single attosecond pulse with high-energy conversion efficiency.