A new kind of quasi-optical resonance system

In order to develop millimeter, sub-millimeter and terahertz waves, we must first seek a proper resonance system. It is well known that the open cavity possesses some advantages, such as low spectral concentration for increasing frequency, high Q-value and feasibility of manufacture. Recently, the open cavity has been widely used in millimeter wave devices, including gyrotrons. A new kind of quasi-optical resonance system based on the Fabry-Perot cavity with either two or three mirrors is proposed and developed in this paper.