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  • Open Access

Control of spectral chirality in high-harmonic generation using two-color bicircular laser fields

N. Zhavoronkov1,*, U. Bengs1, and D. B. Milošević1,2,3

  • *Contact author: zhavoron@mbi-berlin.de
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Phys. Rev. Research 8, 023146 – Published 11 May, 2026

DOI: https://doi.org/10.1103/xtck-9s9n

Abstract

We have extended the two-color bicircular approach for generating chiral XUV radiation via high-harmonic generation by combining femtosecond driving laser fields with 1:3 frequency ratio of wavelengths 1200 and 400 nm. With optimized driving-field intensities, we produced highly chiral spectra in which the vast majority of harmonics sharing the same helicity constitute the vast majority of spectral content. We support these experimental finding with a numerically comprehensive analytical model that describes the propensity (selection) rules for emission of circularly polarized high harmonics. We identify and confirm the rules responsible for the contrast between the allowed odd harmonics of orders 4q+1 and 4q−1 (q an integer), which posses opposite helicities, as well as the complete prohibition of even-order harmonics in the high-harmonic spectra. We further apply these rules to explain the spectral shape and ellipticity of the emitted odd harmonics as functions of both the intensity and the ellipticity of the driving-field components. Using XUV polarimetry, we retrieved full Stokes vector, confirming achieved ellipticities higher than 0.9.

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Phys. Rev. Research 8, 023146– Published 11 May, 2026
  • Received 16 January 2026
  • Accepted 20 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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