Measurements of nonlinear harmonic generation at the Advanced Photon Source's SASE FEL

Research output: Contribution to journalArticle


SASE saturation was recently achieved at the Advanced Photon Source's SASE FFL in the low-energy undulator test line at 530 nm and 385 urn. The electron beam microbunching becomes more and more prominent until saturation is achieved. This bunching causes nonlinear harmonic emission that extends the usefulness of a SASE system in achieving shorter FEL wavelengths for the same electron beam energy. We have investigated the intensity of the fundamental and second harmonic undulator radiation as a function of distance along the undulator line and present the experimental results and compare them to numerical simulations. In addition, we have measured the single-shot second harmonic spectra as well as the simultaneous fundamental and second harmonic spectra and present the experimental results. (C) 2002 Elsevier Science B.V. All riudits reserved.


  • Sandra G. Biedron
  • RJ Dejus
  • Z Huang
  • SV Milton
  • V Sajaev
  • W Berg
  • M Borland
  • PK Den Hartog
  • M Erdmann
  • WM Fawley
  • HP Freund
  • E Gluskin
  • KJ Kim
  • JW Lewellen
  • Y Li
  • AH Lumpkin
  • ER Moog
  • A Nassiri
  • G Wiemerslage
  • BX Yang
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Accelerator Physics and Instrumentation


  • free-electron lasers, harmonic generation, intense particle beams and radiation sources, frequency conversion
Original languageEnglish
Pages (from-to)94-100
JournalNuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment
Issue number1-2
Publication statusPublished - 2002
Publication categoryResearch