A 0.33-THz second-harmonic frequency-tunable gyrotron

Li Zheng-Di^{1, 2}, Du Chao-Hai³, Qi Xiang-Bo³, Luo Li^{1, 2}, Liu Pu-Kun^{3, †,}

Starting oscillation currents of cavity modes near the operating mode TE_−3,4,1 as a function of magnetic field, where dashed lines represent fundamental-harmonic modes while solid lines refer to second-harmonic modes with beam parameters: V_b = 12 kV and α = 1.75.