Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 95: Other And Miscellaneous
O 95.1: Vortrag
Donnerstag, 15. März 2018, 12:00–12:15, MA 144
Sub-Pulse Formation and Limit-Cycle Oscillations in an Infrared FEL Oscillator — •Riko Kießling1, Sandy Gewinner1, Wieland Schöllkopf1, William Bill Colson2, Martin Wolf1, and Alexander Paarmann1 — 1Fritz-Haber-Institut der MPG, Berlin, Germany — 2Naval Postgraduate School, Monterey, California, USA
Due to their high brightness, ultrashort pulse generation and widely tunable spectral range - from THz photons up to hard X-ray radiation - free-electron laser (FEL) light sources provide unique possibilities for scientific research. Besides that, the FEL itself posseses interesting nonlinear dynamics in the relativistic regime governed by short optical pulses and electron bunches.
Here, we present experimental and theoretical investigations on the sub-pulse formation and limit-cycle oscillations in an infrared FEL oscillator. Cavity shortening is found to be critical for the optical pulse creation. Utilizing a cross-correlation technique with a low-jitter synchronized table-top laser, we observe the build-up and evolution of multiple-peaked FEL pulses, composed of ps-short sub-pulses. The resulting oscillations of the emitted FEL power on a micro-second timescale represent a stable limit-cycle mode of the nonlinear FEL electron-photon system. Our observations are in agreement with predictions based on Maxwell-Lorentz theory [1] and might be of relevance also for recently proposed X-ray FEL oscillators [2].
[1] W. B. Colson, Phys. Quantum Electron. 8, 457 (1982)
[2] K.-J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008)