High-order harmonic generation with single mid-infrared laser field by a phase-chirping

By solving the time-dependent Schroedinger equation, we present a theoretical investigation of high-order harmonic and isolated attosecond pulse generation in infrared laser field with phase chirping. It is demonstrated that the yield of the supercontinuum harmonic can be increased and ultrashort isolated attosecond pulse can be obtained by phase chirping. Especially, by the phase of 0.3 π and β = 0.3 in βt, the bandwidth of 822 eV of harmonic spectrum and an isolated 2.7 as pulse can be obtained. Meanwhile, the conversion efficiency of harmonic and intensity of isolated attosecond pulse can be enhanced effectively. (authors)