The optical resonator of the IR-FEL at ELBE


The optical resonator of the IR-FEL at ELBE

Seidel, W.; Evtushenko, P.; Gippner, P.; Grosse, E.; Jainsch, R.; Oepts, D.; Sobiella, M.; Wohlfarth, D.; Wolf, A.; Wolf, U.; Wünsch, R.; Wustmann, B.

To allow first lasing at the ELBE FEL at the end of 2003 various efforts have been made. In particular, the optical resonator including the system which controls and stabilizes its length and alignment has been installed and tested. The resonator length is controlled by means of an interferometer beam passing diagonally from one side of the upstream mirror to a retroreflector on the opposite side of the downstream mirror.
To avoid temperature effects the mirror holders have been equiped with a special heating and cooling system which stabilizes the mirror temperature. Simulating maximum laser power the cavity detuning due to temperature changes has not exceeded 1micron.
The alignment of the resonator axis is controlled by the overlap of two He-Ne laser beams entering the resonator from each side. To predict the outcoupled laser power and the upper wavelength limit we have modeled the IR-beam propagation in the optical resonator. In particular, the vacuum chamber in the undulator, which is 10 mm high, and the outcoupling hole affect the beam power and profile significantly; respective results will be presented.

Keywords: Keine

  • Poster
    25th Int. Conf. on Free Electron Laser, Tsukuba, Ibaraki, Japan, 8 - 12 September 2003
  • Nuclear Instruments and Methods in Physics Research A 528(2004)1-2, 199-202

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Publ.-Id: 5695