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DOI:10.18429/JACoW-FEL2015-WEB04
Title Saturation Dynamics, Fine Spectrum, and Chirp Control in a CW FEL Oscillator
Authors
  • H. S. Marks, A. Gover, H. Kleinman
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  • D. Borodin, A. Damti, A. Friedman, Y. Vashdi
    Ariel University, Ariel, Israel
  • M. Einat, M. Kanter, Y. Lasser, Yu. Lurie, A. Yahalom
    Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
Abstract As in conventional laser physics, the saturation dynamics of a long-pulse Electrostatic Accelerator FEL (EA-FEL) oscillator consists of oscillations build-up, resonator modes competition, and establishment of narrow linewidth single mode lasing. In EA-FEL the gain curve drifts to lower frequencies during the long laser pulse due to inevitable droop in the acceleration voltage. This post-saturation drift renders fine chirp of the single mode laser frequency due to the oscillator frequency pulling effect. We have integrated a voltage-ramping element into the electrostatic accelerator terminal that makes it possible to control the acceleration voltage throughout the lasing pulse. This allows us to keep the voltage constant throughout the e-beam pulse, and so increase the single mode lasing time, avoiding mode-hopping during the pulse due to the drift of the gain curve. Furthermore, by adjusting the voltage ramp rate and polarity we obtained controllable positive/negative laser frequency chirp that can be used in a single pulse sweep for fine spectral line (10⁻⁶) gas-spectroscopy. The study was conducted on the Israeli EA-FEL that operates at tunable frequencies between 95-110 GHz.
Paper download WEB04.PDF [0.545 MB / 3 pages]
Slides download WEB04_TALK.PDF [2.310 MB]
Conference FEL2015, Daejeon, Republic of Korea
Series International Free Electron Laser Conference (37th)
Proceedings Link to full FEL2015 Proccedings
Session FEL Oscillator
Date 26-Aug-15   10:30–12:00
Main Classification FEL Oscillator
Keywords FEL, laser, electron, coupling, operation
Publisher JACoW, Geneva, Switzerland
Editors Heung-Sik Kang (PAL, Pohang, Republic of Korea); Dong Eon Kim (PAL, Pohang, Republic of Korea); Volker RW Schaa (GSI, Darmstadt, Germany);
ISBN 978-3-95450-134-2
Published December 2015
Copyright
Copyright © 2015 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0