Observation of coherent undulator radiation in THz region

Shigeru Kashiwagi, Taro Abe, Hirotoshi Saito, Fujio Hinode, Ken Kanomata, Sadao Miura, Toshiya Muto, Ikuro Nagasawa, Ken ichi Nanbu, Shingo Ninomiya, Nobuyuki Nishimori, Yuki Saito, Ken Takahashi, Hiroyuki Hama

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The generation of coherent THz radiation from femtosecond electron bunches passing through an undulator was demonstrated with a test accelerator as a coherent terahertz source (t-ACTS) at Tohoku University. The velocity bunching scheme in the traveling wave accelerating structure was employed to generate electron bunches much shorter than the THz wavelength. The electron bunch length was measured with the spectrum analysis method for coherent transition radiation. A 2.5-m long undulator with 25 periods and peak magnetic field of 0.41 T was utilized to generate the tunable coherent undulator radiation ranging from 2.6 to 3.6 THz at the t-ACTS. The measured frequency spectrum and spatial distribution of the coherent undulator radiation are presented.

Original languageEnglish
Pages (from-to)335-339
Number of pages5
JournalInfrared Physics and Technology
Publication statusPublished - 2018 Sep


  • Coherent radiation
  • Electron beam
  • Undulator radiation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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