Abstract
Periodical Bragg structures may be considered as an effective way of controlling the electromagnetic energy fluxes and provision of spatially coherent radiation in the free electron lasers with oversized interaction space. A new scheme of terahertz band FEL with hybrid Bragg resonator is proposed consisting of advanced input Bragg mirror and traditional output Bragg mirror. An advanced Bragg mirror exploiting the coupling between the two counterpropagating modes and the quasicutoff one provides mode selection over the transverse index. The main amplification of the wave by the electron beam takes place in the regular section of the resonator. Small reflections from the output traditional Bragg mirror are sufficient for oscillator self-excitation.
Highlights
Reflectors based on Bragg coupling of counterpropagating waves on the periodic structures are widely used both in quantum [1,2] and classical [3,4] electronics
In the millimeter wavelength range, the Bragg structures based on hollow metallic waveguides with periodic corrugation of inner surface allow one to combine the effective electron beam transportation with selective resonance system
In this paper we consider the planar model of the FEL with a hybrid Bragg resonator consisting of two structures with different operating features (Fig. 1): an upstream advanced Bragg reflector and a downstream traditional Bragg reflector
Summary
Reflectors based on Bragg coupling of counterpropagating waves on the periodic structures are widely used both in quantum [1,2] and classical [3,4] electronics. The advance in shorter wave bands is limited because at large values of the oversize factor the coupling between numerous pairs of propagating modes occurs. The problem of extending of the interaction space in the transverse direction can be partially solved by using the coupling between the propagating and the cutoff modes in the advanced Bragg reflector with additional transverse electromagnetic energy fluxes [5]. Mode control in the transverse (y) direction is achieved within the upstream advanced Bragg reflector by means of the above-described mechanism of partial waves coupling. In the Appendix some guidelines on the derivation of the basic equations are given
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
