Theory of free electron laser with terahertz band Bragg reflector

Summary form only given. Reflectors based on Bragg coupling of counter propagating waves on the periodic structures are widely used both in quantum and classical electronics. In the millimeter wavelength range the Bragg structures formed by hollow metallic waveguides with periodic corrugation of inner surface allow one to combine the effective electron beam transportation with selective resonance system. However, the advance in shorter wave bands is limited because at large oversize factors the coupling between numerous pairs of propagating modes occurs. As a result, the radiation generated by the electron beam will represent an uncontrolled mixture of the waveguide modes.