Control of high-order harmonic generation with chirped inhomogeneous fields

We theoretically investigate high-order harmonic generation (HHG) in the chirped inhomogeneous field. The results show that by using a chirped pulse, the HHG in the inhomogeneous field can be efficiently controlled. The harmonic cutoffs can be extended. Supercontinua with photon energies ranging from 201 to 263 eV and isolated attosecond pulses with durations less than 90 as are produced without carrier -envelope phase stabilization. Furthermore, it is shown that our scheme is robust against the variation of the inhomogeneity of the laser field. All our results are well explained by the quantum and classical analysis. (C) 2017 Optical Society of America