Harmonic extension and attosecond pulse generation by using the modified three-color chirped pulse

TLDR: In this article, a model He atom is exposed to the modified three-color chirped field (800 nm+1600 nm+1200 nm) and it is found that when the chirp parameters are chosen to be (1) = 0.3 (corresponding to the 800-nm field), (2) =0.6 (corcerning to the 1600-nm fields) and (3) = -0.2 (approximately corresponding to the 1200-nm Fields), the harmonics have an optimal extension resulting in a 491 eV bandwidth.

Abstract: Through numerical solution of the quasi-three-dimensional time-dependent Schrodinger equation, the harmonic spectra and attosecond-pulse generation have been theoretically investigated when a model He atom is exposed to the modified three-color chirped field (800 nm+1600 nm+1200 nm). It is found that when the chirp parameters are chosen to be (1) = 0.3 (corresponding to the 800-nm field), (2) = 0.6 (corresponding to the 1600-nm field) and (3) = -0.2 (corresponding to the 1200-nm field), the harmonics have an optimal extension resulting in a 491 eV bandwidth. Further, an isolated 32-as pulse is directly achieved with proper harmonic superposition.