A practical scheme for generating isolated elliptically polarized attosecond pulses using bi-chromatic counter rotating circularly polarized laser fields

TL;DR

This paper presents a practical method to generate isolated elliptically polarized attosecond pulses by using bi-chromatic counter-rotating circularly polarized laser fields, with numerical simulations demonstrating the approach.

Contribution

The study introduces a novel scheme employing counter-rotating circularly polarized laser fields and a time-shift technique to produce isolated elliptically polarized attosecond pulses.

Findings

Asymmetry between left- and right-circularly polarized harmonics observed.

Shortening the driver pulses and adding a time-shift enables single elliptically polarized attosecond pulse.

Numerical simulations confirm the effectiveness of the proposed scheme.

Abstract

Spectra of circularly polarized harmonics is calculated by numerically solving the Time-Dependent Schr\"{o}dinger Equation for a 2D model of Ne atom using circularly polarized fundamental with counter-rotating second harmonic laser fields. We demonstrate strong asymmetry between left- and right- circularly polarized harmonics when a ground state with p-type symmetry is used. It arises due to the circular polarization of individual attosecond pulses in the generated pulse train. Reducing the length of the counter-rotating drivers and introducing a small time-shift between them allows to generate a single elliptically polarized attosecond pulse.