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Coherence and superradiance from a plasma-based quasiparticle accelerator


Coherent light sources, such as free-electron lasers, provide bright beams for studies in biology, chemistry and physics. However, increasing the brightness of these sources requires progressively larger instruments, with the largest examples, such as the Linac Coherent Light Source at Stanford, being several kilometres long. It would be transformative if this scaling trend could be overcome so that compact, bright sources could be employed at universities, hospitals and industrial laboratories. Here we address this issue by rethinking the basic principles of radiation physics. At the core of our work is the introduction of quasiparticle-based light sources that rely on the collective and macroscopic motion of an ensemble of light-emitting charges to evolve and radiate in ways that would be unphysical for single charges. The underlying concept allows for temporal coherence and superradiance in new configurations, such as in plasma accelerators, providing radiation with intriguing properties and clear experimental signatures spanning nearly ten octaves in wavelength, from the terahertz to the extreme ultraviolet. The simplicity of the quasiparticle approach makes it suitable for experimental demonstrations at existing laser and accelerator facilities and also extends well beyond this case to other scenarios such as nonlinear optical configurations.

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Fig. 1: Nonlinear plasma wakefields and their radiation.
Fig. 2: Onset of quasiparticle Cherenkov emission.
Fig. 3: Quasiparticle Cherenkov radiation in a LWFA.
Fig. 4: Quasiparticle undulator radiation for an oscillating quasiparticle with ωc = 0.1ωp and Δxc = 0.25c/ωp.
Fig. 5: Peak brightness estimated as a function of photon energy for nonlinear wakefield quasiparticle radiation, spanning frequencies ranging from terahertz to extreme ultraviolet.

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Data availability

Due to the large size of the datasets, all data that support the plots within this paper and the other findings of this study are available from the corresponding author upon reasonable request.

Code availability

All computer codes supporting the findings of this study are fully documented within the paper and its references. Reasonable requests for access to the codes should be directed to J.V. or R.A.F. on behalf of the Osiris consortium.


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We would like to acknowledge very fruitful interactions and discussions with L. Silva, R. Bingham, R. Trines and Z. Najmudin. We acknowledge use of the Marenostrum (Spain) and LUMI (Finland) supercomputers through PRACE/EuroHPC awards. Fundação para a Ciência e Tecnologia, Portugal, supports the work of B.M. (Grant No. PD/BD/150409/2019) and M.P. (Grant No. PD/BD/150411/2019). The European Union EuPRAXIA Preparatory Phase Project (Grant No. 653782) supports the work of J.V. and R.A.F. The Office of Fusion Energy Sciences (Award No. DE-SC00215057), the Department of Energy National Nuclear Security Administration (Award No. DE-NA0003856), the University of Rochester and the New York State Energy Research and Development Authority support the work of D.R., K.W. and J.P.P. The National Science Foundation (Award No. 2108970) and Department of Energy National Nuclear Security Administration (Award No. DE-NA0004131) supports the work of J.R.P. and W.B.M.

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B.M. and J.V. developed the concept and the corresponding theory. M.P., J.V. and R.A.F. developed the main simulation codes and the numerical tools. B.M. performed the simulations and analysed the data. B.M., J.V. and J.P.P. wrote the manuscript and Supplementary Information with inputs from all authors. All authors provided critical feedback and conceptual expertise for the overall idea.

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Correspondence to B. Malaca or J. Vieira.

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Nature Photonics thanks James Rosenzweig and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Malaca, B., Pardal, M., Ramsey, D. et al. Coherence and superradiance from a plasma-based quasiparticle accelerator. Nat. Photon. (2023).

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