Feasible Design of a Free Electron Laser Based on the Smith–Parsell Effect

A free electron laser design is considered in which coherent radiation is generated during the flight of a bunched electron beam near a periodic metal target (Smith–Parsell radiation). If the target (array) is placed in a special resonator, optical feedback can be realized. It is proposed to use an array made of thin conductive strips separated with vacuum gaps, since the radiation output in this case is much higher than that attainable with conventional arrays. Varying the array parameters, one can choose the necessary direction and required spectral distribution of the Smith–Parsell radiation. When radiation is generated in the direction normal to the trajectory of the electron beam, the array acts as one of the resonator mirrors.