An ignition feedback regenerative amplifier consists of an injector, a linear accelerator with energy recovery, and a high-gain free electron laser amplifier. A fraction of the free electron laser output is coupled to the input to operate the free electron laser in the regenerative mode. A mode filter in this loop prevents run away instability. Another fraction of the output, after suitable frequency up conversion, is used to drive the photocathode. An external laser is provided to start up both the amplifier and the injector, thus igniting the system.
The United States Government has rights in this invention pursuant to Contract No. DE-AC03-76SF00098 between the U.S. Department of Energy and the University of California, for the operation of Lawrence Berkeley National Laboratory and Agreement BG97-100(00) between Lawrence Berkeley National Laboratory and the City of Ridgecrest, Calif.