摘要 : We propose a scheme to generate isolated attosecond (as) pulses by high-peak-power multicycle laser fields which is based on high-order harmonics generation ( HHG) from a helium atom irradiated by a three-color fennosecond (fs) la... 展开 We propose a scheme to generate isolated attosecond (as) pulses by high-peak-power multicycle laser fields which is based on high-order harmonics generation ( HHG) from a helium atom irradiated by a three-color fennosecond (fs) laser field. An infrared laser acts as the driving laser and two tunable lasers act as control fields which are used to modulate the ellipticity and amplitude of the driving field respectively. With well-chosen parameters, an isolated 100 as pulse is generated with a duration of 50 fs. 收起