Breakdown of the single-collision condition for soft x-ray high harmonic generation in noble gases
Open access
Date
2022-12-20Type
- Journal Article
Abstract
High harmonic generation (HHG) in atomic gases is generally assumed to originate from photoelectrons that are not perturbed by neighboring particles. In this paper, we study theoretically and experimentally the regime where this approximation breaks down. At high laser intensities, we experimentally find that producing soft x-rays beyond this single-collision condition leads to a strong reduction of the coherent HHG response and appearance of incoherent radiation. We generalize our results to phase-matched HHG with mid-infrared drivers, and determine that a minimum pulse energy is needed to simultaneously phase match the HHG process and keep photoelectrons unperturbed by surrounding particles. Therefore, while previous research showed that HHG efficiency is independent of the driving pulse energy if other experimental parameters are scaled accordingly, we find that this rule no longer applies for high photon energies. Our study thus provides important guidelines for the laser parameters needed for the generation of high flux soft x-ray high harmonics. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000588540Publication status
publishedExternal links
Journal / series
OpticaVolume
Pages / Article No.
Publisher
OpticaSubject
Laser physics; high harmonic generation; Ultrafast phenomena; Soft X-ray; attosecond physicsOrganisational unit
03371 - Keller, Ursula / Keller, Ursula
08733 - Gallmann, Lukas (Tit.-Prof.) / Gallmann, Lukas (Tit.-Prof.)
Funding
200416 - High repetition rate attosecond pulse generation (SNF)
Related publications and datasets
Is supplemented by: https://doi.org/10.3929/ethz-b-000581229
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