Control the high-order harmonics cutoff through the combination of chirped laser and static electric field

TL;DR

This paper theoretically investigates how combining chirped laser pulses with static electric fields can significantly extend high harmonic generation cutoffs and produce ultrabroad super-continuum spectra, enabling isolated attosecond pulses.

Contribution

It introduces a new physical mechanism for extending HHG cutoff using combined fields and demonstrates the generation of ultrabroad spectra and isolated attosecond pulses.

Findings

Cutoff extended to Ip+42Up with proper parameters.

Ultrabroad super-continuum spectrum generated.

Isolated 9-attosecond pulse achieved.

Abstract

The high harmonic generation from atoms in the combination of chirped laser pulse and static field is theoretically investigated. For the first time, we explore a further physical mechanism of the significant extension of high harmonic generation cutoff based on three-step model. It is shown that the cutoff is substantially extended due to the asymmetry of the combined field. If appropriate parameters are chosen, the cutoff of high harmonic generation can reach Ip+42Up. Furthermore, an ultrabroad super-continuum spectrum can be generated. When the phases are properly compensated for, an isolated 9 attosecond pulse can be obtained.