Twisting attosecond pulse trains by amplitude-polarization IR pulses

TL;DR

This paper introduces a novel method to generate twisted attosecond pulse trains with controlled polarization angles using amplitude-polarized IR pulses, enhancing ultrafast probing capabilities.

Contribution

It proposes a new scheme to produce polarization-controlled attosecond pulse trains via high-order harmonic generation driven by amplitude-polarized IR pulses, with detailed quantum simulations.

Findings

Achieved high control over polarization angles of attosecond pulses.

Demonstrated the feasibility of polarization sculpting in XUV radiation.

Provided insights into the physics of polarization control in HHG.

Abstract

Natively, atomic and molecular processes develop in a sub-femtosecond time scale. In order to, for instance, track and capture the electron motion in that scale we need suitable `probes'. Attosecond pulses configure the most appropriate tools for such a purpose. These ultrashort bursts of light are generated when a strong laser field interacts with matter and high-order harmonics of the driving source are produced. In this work, we propose a way to twist attosecond pulse trains. In our scheme, each of the attosecond pulses in the train has a well-defined linear polarization, but with a different polarization angle between them. To achieve this goal, we consider an infrared pulse with a particular polarization state, called amplitude polarization. This kind of pulse was experimentally synthesized in previous works. Our twisted attosecond pulse train is then obtained by nonlinear driving an atomic system with that laser source, through the high-order harmonics generation phenomenon. We reach a high degree of control in the polarization of the ultrashort coherent XUV-generated radiation. Through quantum mechanical simulations, supplemented with signal processing tools, we are able to dissect the underlying physics of the generation process. We are confident these polarized-sculpted XUV sources will play an instrumental role in future pump-probe-based experiments.