Investigation of S-P FEL Quasi-optical Open Resonator with Threats Mirrors

S-P FEL quasi-optical open resonator system with three-mirror are introduced in this paper. By means of the diffracted theory of quasi-optical resonator, this paper analyzes and calculates the characteristics of the system by the principle of mirror symmetry and the method of rotating coordinate system. The corresponding model charts and testing results on 3 mm band are given. The numerical simulation and experimental results show that the method is effective.