Observation of Amplified Stimulated Terahertz Emission from Optically Pumped Heteroepitaxial Graphene-on-Silicon Materials

  • Hiromi Karasawa
  • Tsuneyoshi Komori
  • Takayuki Watanabe
  • Akira Satou
  • Hirokazu Fukidome
  • Maki Suemitsu
  • Victor Ryzhii
  • Taiichi Otsuji


We experimentally observed the fast relaxation and relatively slow recombination dynamics of photogenerated electrons/holes in a heteroepitaxial graphene-on-Si material under pumping with a 1550-nm, 80-fs pulsed fiber laser and probing with the corresponding terahertz beam generated by and synchronized with the pumping laser. The time-resolved electric-nearfield intensity originating from the coherent terahertz photon emission is electrooptically sampled in total-reflection geometry. The Fourier spectrum fairly agrees the product of the negative dynamic conductivity and the expected THz photon spectrum reflecting the pumping photon spectrum. This phenomenon is interpreted as an amplified stimulated terahertz emission.


Graphene Terahertz Negative-dynamic conductivity Population inversion Stimulated emission GOS Coherent 



The authors thank Yu Miyamoto and Hiroyuki Handa at RIEC, Tohoku University, Japan for their providing graphene-on-silicon samples, and also Maxim Ryzhii at University of Aizu for his valuable discussion. This work was financially supported in part by the JST-CREST program, Japan, and a Grant-in-Aid for Basic Research (S) from the Japan Society for the Promotion of Science.


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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Hiromi Karasawa
    • 1
  • Tsuneyoshi Komori
    • 1
  • Takayuki Watanabe
    • 1
  • Akira Satou
    • 1
    • 3
  • Hirokazu Fukidome
    • 1
    • 3
  • Maki Suemitsu
    • 1
    • 3
  • Victor Ryzhii
    • 2
    • 3
  • Taiichi Otsuji
    • 1
    • 3
  1. 1.Research Institute of Electrical CommunicationTohoku UniversitySendaiJapan
  2. 2.Depertment of Computer Science and EngineeringUniversity of AizuAizu-WakamatsuJapan
  3. 3.JST-CRESTTokyoJapan

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