A design of a Bragg reflector for a Raman FEL is described. It is shown that mode conversion occurs whenever the axial wavenumbers of the two modes fulfil the Bragg condition. With a constant ripple of the corrugation it is shown that the reflected radiation also contains higher order modes, assuming that the incident radiation consists only of a TE11 mode. The mode purity can be increased by increasing the length of the reflector at the expense of a smaller reflection bandwidth. A more flexible method is by applying a Hamming window to the corrugation of the reflector. Contributions of other modes to the reflected radiation can in that case be neglected. The reflector will be installed in a Raman laser to be able to compare the amplifier with the oscillator configuration. Therefore some preliminary results are also presented about the start-up of the Raman laser.
|Number of pages||5|
|Journal||Nuclear instruments & methods in physics research. Section A : Accelerators, spectrometers, detectors and associated equipment|
|Publication status||Published - 1994|
|Event||15th International Free Electron Laser Conference, FEL 1993 - Netherlands Congress Centre, The Hague, Netherlands|
Duration: 23 Aug 1993 → 27 Aug 1993
Conference number: 15