Using Special Three-mirror Quasi-optical Resonator Diffraction Radiation Oscillator

The diffraction radiation oscillator is a sort of new vacuum electronic with an open resonator and reflecting grating, This device is base on the Smith-Purcell effect. But it is confined for it's efficiency and the machining of grating when the wavelength is more short. A new scheme has considered :a quasi-optical resonator composed of diffraction grating and three-mirror reflector. the considerable advantage as follow: ring beam enable more high beam current to transmit steadily and to taken shape easily , Three-mirror have a special the field profiles and quality factor, Besides, energy output system of this resonator is facility and credibility ,so the output power and efficiency can be improved evidently.This dissertation studies some theory about the cavity and the diffraction grating, the computer simulation by the PIC(Particle In Cell) code MAGIC.A very good agreement has achieved among them, and then presents a special kind of three-mirror quasi-optical cavity that work on the second evanescent. The simulation show it great potential to develop a compact, powerful and coherent radiation source working in room temperature. The works done in this dissertation listed as the following:1) We research the problem how the dispersion of rectangle grating is influenced by the parameters of the grating separately. Then in combination the theoretical analyses with Particle-in-Cell(PIC) simulations, the physical mechanisms of the coherent radiation of continued electrons beam passing the planar rectangular grating is studied .The results show that the harmonious electromagnetic waves of evanescent are the radiate wave, which is equal to the frequency of the Smith-Purcell at some angle.2) Analyses the theory of interaction between the electromagnetic and the beams. We prove the possibility with the PIC, that the second evanescent wave can be surged by the three-mirror cavity which has the property of election for the electromagnetic and feedback mechanisms.3) Combines the power generated of the three-mirror cavity, a new kind of the model has been proposed, which shows it's a great potential to develop a compact, powerful and coherent THz radiation source. Theory and number simulation indicated the axis-symmetry circumrotate cavity are efficiency and prospect than the traditional resonator, the ring beam enable more high beam current transmit steadily and be taken shape easily.It is a good reference for further development on THz radiation source base on the mechanism in vacuum electronic.