Generation of Attosecond Pulses with Controllable Carrier-Envelope Phase via High-order Frequency Mixing

TL;DR

This paper investigates high-order frequency mixing (HFM) as a promising method for generating bright, controllable attosecond pulses, offering advantages over traditional high-order harmonic generation (HHG) in phase control and pulse duration.

Contribution

It provides analytical and numerical insights into HFM-generated attosecond pulses, highlighting phase controllability and pulse duration characteristics distinct from HHG.

Findings

HFM can produce shorter attosecond pulses in the cut-off region.

The carrier-envelope phase of HFM attopulses can be easily controlled.

HFM is more efficient than HHG in certain regimes.

Abstract

Advancing table-top attosecond sources in brightness and pulse duration is of immense interest and importance for an expanding sphere of applications. Recent theoretical studies [New J. Phys., 22 093030 (2020)] have found that high-order frequency mixing (HFM) in a two-color laser field can be much more efficient than high-order harmonic generation (HHG). Here we study the attosecond properties of the coherent XUV generated via HFM analytically and numerically, focusing on the practically important case when one of the fields has much lower frequency and much lower intensity than the other one. We derive simple analytical equations describing intensities and phase locking of the HFM spectral components. We show that the duration of attosecond pulses generated via HFM, while being very similar to that obtained via HHG in the plateau, is shortened for the cut-off region. Moreover, our study demonstrates that the carrier-envelope phase of the attopulses produced via HFM, in contrast to HHG, can be easily controlled by the phases of the generating fields.