High-intensity attosecond pulse generation by using inhomogeneous laser field in frequency and space

High-order harmonic spectra and attosecond source generation from Ar atom driven by the inhomogeneous laser field in frequency and space have been theoretically investigated. The results showed that (i) for the case of the frequency modulation of the laser, the harmonic cutoff can be remarkably extended with the introduction of the chirp of the laser field, (ii) for the case of the space modulation of the laser, the harmonic cutoff can be further extended by using the positive spatial inhomogeneous field, (iii) by properly adding a terahertz controlling field, the intensity of the harmonic yield can be enhanced by 2 orders of magnitude, showing a 775[Formula: see text]eV supercontinuum. As a result, five isolated attosecond pulses (IAPs) from 60 as to 22 as can be obtained.