Quantum wavepacket exploration of isolated high-order harmonic attosecond pulse generation: from two-color scheme to three-color scheme

Isolated attosecond generation under the two-color scheme and three-color scheme are investigated theoretically by use of wave-packet dynamics calculation. Optimized relative phase under the two-color field is obtained and comparison is taken between the second-harmonic control and half-harmonic control. A further exploration of the three-color scheme by adding a weak second-harmonic pulse and a half-harmonic pulse onto 8 x 10(14) W cm(-2) 6 fs/800nm pulse shows the potential for generating the 337 eV continuum supporting creation of an isolated 11 as pulse.