Initial experimental results for a 400GHz second harmonic gyrotron with quasi-optical confocal cavity

To develop high harmonic terahertz gyrotron, gyrotron with quasi-optical confocal cavity has been studied. Theoretical studies show quasi-optical confocal cavity has good mode selectivity and could be adopted in high harmonic gyrotron. A 400 GHz second harmonic gyrotron with confocal cavity is designed and experimented. In initial experiment, 396GHz second harmonic output with 1.5 kW power is observed.