Centers & Labs

RIKEN Center for Advanced Photonics

Terahertz Quantum Device Research Team

Team Leader: Hideki Hirayama (D.Eng.)
Hideki  Hirayama(D.Eng.)

We develop advanced terahertz emitting and sensing devices based on inter sub-band optical transition of semiconductor quantum cascade structures. Firstly, we design and fabricate novel quantum cascade superlattice (SL) structures for high-efficiency terahertz transitions and develop terahertz quantum cascade laser (QCLs) with frequency range between 1-100 THz. We also develop high-sensitivity terahertz-wave detectors and terahertz-infrared (IR) light modulators using inter sub-band absorption of quantum wells. We hope through this research to construct what will become the base of the next-generation advanced terahertz imaging system.

Main Research Field


Related Research Fields

Interdisciplinary science and engineering


  • Terahertz
  • Quantum cascade laser
  • Inter-subband transition emission
  • Nitride Semiconductors
  • Crystal growth

Selected Publications

  1. Lin, T.T., and Hirayama, H.:
    "Improvement of operation temerature in GaAs/AlGaAs THz-QCLs by utilizing high Al conposition barrier"
    Phys. Status Solidi (c), vol. 10, no. 11, pp. 1430-1433 (2013).
  2. Sasaki, M., Lin, T.T., and Hirayama, H.:
    "1.9 THz selective injection design quantum cascade laser operating at extreme higher temperature above kBT line"
    Phys. Status Solidi (c), Vol. 10, No. 11, pp. 1448-1451 (2013).
  3. Terashima, W. and Hirayama, H.:
    "Intersubband spontaneous emission from GaN-based THz quantum cascade laser"
    Gallium Nitride Materials and Devices VIII in OPTO, Proc. of SPIE Photonic West (2013).
  4. Lin, T.T., Ying, L., and Hirayama, H.:
    "Threshold current density reduction by utilizing high-Al-composition barriers in 3.7 THz GaAs/AlGaAs quantum cascade lasers"
    Appl. Phys. Express, Vol. 5, 012101 (2011).
  5. Terashima, W. and Hirayama, H.:
    "Development of terahertz quantum cascade laser based on III-nitride semiconductors"
    The Review of Laser Engineering, Vol. 39, No. 10, pp. 769-774 (2011).
  6. Terashima, W. and Hirayama, H.:
    "Molecular beam epitaxy growth of GaN/AlGaN quantum cascade structure using droplets elimination by thermal annealing technique"
    Phys. Status Solidi A Vol. 208, No. 5, pp. 1187-1190 (2011).
  7. Terashima, W. and Hirayama, H.:
    "The utility of droplet elimination by thermal annealing technique for fabrication of GaN/AlGaN terahertz quantum cascade structure by radio frequency molecular beam epitaxy"
    Appl. Phys. Express Vol. 3, No. 12, 125501-1-3 (2010).
  8. Terashima, W. and Hirayama, H.:
    "Design and fabrication of terahertz quantum cascade structure based on III-Nitride semiconductors"
    Physica Status Solidi (c), Vol. 6, No. S2, pp. S614-S617 (2009).

Lab Members

Principal Investigator

Hideki Hirayama
Team Leader

Core Members

Wataru Terashima
Research Scientist
TsungTse Lin
Research Scientist
Masafumi Jo
Research Scientist
Ke Wang
Research Scientist
Noritoshi Maeda
Technical Scientist
Tinh Binh Tran
Foreign Postdoctoral Researcher

Contact information

Terahertz Research Building 304
519-1399 Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
Tel: +81-(0)22-228-2035
Fax: +81-(0)22-228-2017

Email: hirayama [at]

Related links