Spectral phase control for optimized ionization injection in laser wakefield acceleration
Generating narrow energy spread beams from laser wakefield accelerators with minimal dark current is important for many applications. We present an automated experiment using Bayesian optimization to control the laser spectral phase and focal position, achieving significant enhancement of the beam quality. Starting from a broadband spectrum, the optimized configuration achieved low-energy spread with negligible dark current above 20 MeV. Particle-in-cell simulations reveal that fine control over the laser spectral phase, particularly third-order dispersion, directly impacts the timing and localization of ionization injection due to its effect on the initial laser intensity envelope and its subsequent evolution. A positively skewed temporal profile enhances the plasma potential depth at the right location, enabling localized injection and reducing the energy spread and dark current. These findings highlight the impact of algorithmic optimization and the powerful, underutilized role of temporal shaping in beam quality control.
Authors
- S. Dobosz Dufrénoy (ORCID: https://orcid.org/0000-0003-4243-6876)
- F. Massimo (ORCID: https://orcid.org/0000-0002-5686-2537)
- Michael Backhouse (ORCID: https://orcid.org/0009-0005-5594-9154)
- Kristoffer Svendsen (ORCID: https://orcid.org/0000-0002-4326-4861)
- S. J. D. Dann (ORCID: https://orcid.org/0000-0002-6875-631X)
- E. Löfquist (ORCID: https://orcid.org/0009-0008-5916-0224)
- C. D. Murphy (ORCID: https://orcid.org/0000-0003-3849-3229)
- R. J. Shalloo (ORCID: https://orcid.org/0000-0002-9568-3814)
- Cornelia Gustafsson (ORCID: https://orcid.org/0009-0004-7566-188X)
- F. Filippi (ORCID: https://orcid.org/0000-0002-8983-556X)
- L. T. Dickson (ORCID: https://orcid.org/0000-0002-5200-7525)
- I. Moulanier (ORCID: https://orcid.org/0000-0001-7117-6730)
- Z. Najmudin (ORCID: https://orcid.org/0000-0001-6323-4005)
- O. Lundh (ORCID: https://orcid.org/0000-0003-0907-8982)
- M. J. V. Streeter (ORCID: https://orcid.org/0000-0001-9086-9831)
- Charles Ballage (ORCID: https://orcid.org/0000-0003-3301-9069)
- O. Vasilovici
- B. Cros (ORCID: https://orcid.org/0000-0002-3342-2010)
- C. C. Cobo (ORCID: https://orcid.org/0000-0001-6587-5973)
Institutions
- Queen's University Belfast (GB)
- University of Strathclyde (GB)
- Lund University (SE)
- Deutsches Elektronen-Synchrotron DESY (DE)
- Imperial Valley College (US)
- Centro Laser (IT)
- Laboratoire Interactions, Dynamiques et Lasers (FR)
- Central Laser Facility
- University of York (GB)
Publication Details
- Journal
- Physical Review Accelerators and Beams
- Published
- 2025-10-31
- DOI
- https://doi.org/10.1103/9gjq-htzn
- Primary Topic
- Laser-Plasma Interactions and Diagnostics
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- European Commission
- Knut och Alice Wallenbergs Stiftelse
- Vetenskapsrådet
- Centre National de la Recherche Scientifique
- Defence Science and Technology Laboratory
- Engineering and Physical Sciences Research Council
- Science and Technology Facilities Council