Polarization control of attosecond pulses using bi-chromatic elliptically polarized laser

TL;DR

This paper investigates how to control the polarization of attosecond pulses generated via high-harmonic generation using bi-chromatic elliptically polarized laser fields, proposing a setup and a scaling law for tuning ellipticity.

Contribution

It introduces a simple method to control attosecond pulse polarization by modifying driver field ellipticity and derives a scaling law based on TDSE solutions.

Findings

A controllable setup for attosecond pulse polarization.

A scaling law relating ellipticity to wave plate rotation angle.

Potential to generate pulses from linear to circular polarization.

Abstract

We study the higher-harmonic generation (HHG) using elliptically polarized two-color driving fields. The HHG via bi-chromatic counter-rotating laser fields is a promising source of circularly polarized ultrashort XUV radiation at the attosecond time scale. The ellipticity or the polarization of the attosecond pulses can be tweaked by modifying the emitted harmonics' ellipticity, which can be controlled by varying the driver fields. We propose a simple setup to control the polarization of the driving fields, which eventually changes the ellipticity of the attosecond pulses. A well-defined scaling law for the ellipticity of the attosecond pulse as a function of the rotation angle of the quarter-wave plate is also deduced by solving the time-dependent Schrodinger equation (TDSE) in two dimensions. The scaling law can further be explored to obtain the attosecond pulses of the desired degree of polarization, ranging from linear to elliptical to circular polarization.