Abstract: A free-electron laser (FEL), which in a preferred embodiment comprises a relativistic electron beam generator; an optical cavity capable of storing a co-propagating optical beam; an interaction region; a phase displacement device disposed in the interaction region; and an output coupler interposed in the optical cavity through which a predetermined portion of the co-propagating optical beam exits as a coherent output optical beam. In certain embodiments, an optical beam spectral filter may be interposed in the optical cavity. FEL components and methods of use are also disclosed. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope of meaning of the claims.

Abstract: A free-electron laser (FEL), which in a preferred embodiment comprises a relativistic electron beam generator; an optical cavity capable of storing a co-propagating optical beam; an interaction region; a phase displacement device disposed in the interaction region; and an output coupler interposed in the optical cavity through which a predetermined portion of the co-propagating optical beam exits as a coherent output optical beam. In certain embodiments, an optical beam spectral filter may be interposed in the optical cavity. FEL components and methods of use are also disclosed. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope of meaning of the claims.