Influence of Reflections on Frequency Tunability and Mode Competition in the Second-Harmonic THz Gyrotron

  • Eduard M. KhutoryanEmail author
  • Toshitaka Idehara
  • Maria M. Melnikova
  • Nikita M. Ryskin
  • Olgierd Dumbrajs


Effect of delayed reflection on operation of a second-harmonic terahertz (THz)-band gyrotron is studied. Theoretical analyses, numerical calculations, and experimental observations for the 0.394-THz Fukui University (FU) and continuous wave (CW) IIB gyrotron are presented. The reflections decrease starting current and expand frequency tunability range owing to excitation of high-order axial modes. They also increase frequency stability, i.e., reduce frequency change due to variation of the magnetic field. In addition, the reflections strongly affect mode competition causing suppress of the second-harmonic mode by the fundamental one and vice versa or, in the case of cooperative mode interaction, mutual power increase.


Gyrotron Second harmonic Mode competition Reflection Frequency tunability 



N.M.R. and M.M.M. acknowledge financial support from the Russian Foundation for Basic Research grant no 15-02-01798a.


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Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Eduard M. Khutoryan
    • 1
    • 2
    Email author
  • Toshitaka Idehara
    • 1
  • Maria M. Melnikova
    • 3
  • Nikita M. Ryskin
    • 3
    • 4
  • Olgierd Dumbrajs
    • 1
    • 5
  1. 1.Research Center for Development of Far-Infrared RegionUniversity of FukuiFukuiJapan
  2. 2.O. Ya. Usikov Institute for Radiophysics and Electronics IRE NASUKharkivUkraine
  3. 3.Saratov State UniversitySaratovRussia
  4. 4.Saratov Branch, Institute of Radio Engineering and Electronics RASSaratovRussia
  5. 5.Institute of Solid State PhysicsUniversity of LatviaRigaLatvia

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