Demonstration of a High Power Frequency-Tunable 0.22-THz Gyrotron Operating in High-Order Axial Modes

To explore the approach for generating high power frequency-tunable sub-THz to THz radiation, a 0.22-THz high-order axial modes (HOAMs) gyrotron is developed and tested in TRC-UESTC. The proof-of-principle experimental results demonstrate that a series of HOAMs in a long gyrotron cavity are excited successfully by an electron beam of high voltage and high current. A frequency tuning range of 0.79 GHz around 219 GHz has been achieved by tuning the operating magnetic field and operating in the first four axial modes. And during the frequency tuning, the out power kept no less than 0.45 kW, while the maximum output power was 3.80 kW. These experimental results of axial mode transition in high power sub-terahertz gyrotron should be conductive to the future development of frequency-tunable gyrotron towards some up-and-coming novel terahertz applications.