Elliptically polarized high-harmonic radiation for production of isolated attosecond pulses

Ulrich Bengs,Nickolai Zhavoronkov

doi:10.1038/s41598-021-88557-1

Ulrich Bengs, Nickolai Zhavoronkov

Open Access

https://doi.org/10.1038/s41598-021-88557-1

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Abstract

Circularly polarized attosecond pulses are powerful tool to study chiral light-matter interaction via chiral electron dynamics. However, access to isolated circularly polarized attosecond pulses enabling straightforward interpretation of measurements, still remains a challenge. In this work, we experimentally demonstrate the generation of highly elliptically polarized high-harmonics in a two-color, bi-circular, collinear laser field. The intensity and shape of the combined few-cycle driving radiation is optimized to produce a broadband continuum with enhanced spectral chirality in the range of 15-55 eV supporting the generation of isolated attosecond pulses with duration down to 150 as. We apply spectrally resolved polarimetry to determine the full Stokes vector of different spectral components of the continuum, yielding a homogenous helicity distribution with ellipticity in the range of 0.8-0.95 and a negligible unpolarized content.

Highlights

Polarized attosecond pulses are powerful tool to study chiral light-matter interaction via chiral electron dynamics
It is a remarkable result especially taking into account the relatively moderate ellipticity of the second harmonic driver of ε = 0.88
Fundamental circularly polarized beam and the contribution from the elliptical second harmonic beam is of minor importance

Summary

Introduction

Polarized attosecond pulses are powerful tool to study chiral light-matter interaction via chiral electron dynamics. We experimentally utilize for a first time the two-colour bi-circular approach with few-cycle driving laser pulses to generate a XUV-continuum spanning up to 55 eV promising to support highly elliptical isolated attosecond pulses.

Results

Conclusion