Experiments of a Raman free electron laser with distributed feedback cavity

Abstract A design of a free electron laser with distributed feedback has been proposed. Experiments of a Raman free electron laser with a Bragg cavity have made progress in SIOFM. Results of producing 14 MW peak power at 7.7 mm wavelength with 4.4% extraction efficiency using a 400 keV/800 A electron beam of 60 ns duration are reported. The radiation spectrum is measured and a bandwidth narrower than typical superradiation indicated that there is an oscillation in our device.