Coherent dynamics of excitons in a stack of self-assembled InAs quantum dots at 1.5-μm waveband

J. Ishi-Hayase, K. Akahane, N. Yamamoto, M. Kujiraoka, J. Inoue, K. Ema, M. Tsuchiya, M. Sasaki

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We investigate the excitonic dephasing in a stack of self-assembled quantum dots (SAQDs) by using a four-wave-mixing (FWM) technique performed in the optical telecomm-fiber wavelength region at 6 K. A sample used in our experiment is a 150-layer stack of InAs SAQDs embedded in InGaAlAs grown on InP(3 1 1)B substrate fabricated by molecular beam epitaxy. By using a novel strain-controlled technique, the resonant wavelength of the exciton ground state (GS) ranges from 1.25 to 1.5 μm which is much longer than that in typical In(Ga)As SAQDs. In the weak excitation region, the intrinsic dephasing time of excitons at the excitation wavelength of 1.43 μm reaches 770 ps which is much longer than that in most SAQDs with the resonant wavelength of <1 μm. We also find a strong anisotoropy of the signal intensity with respect to the crystal axis attributed to the orientation of InP(3 1 1)B substrate and the elongated shape of QDs.

Original languageEnglish
Pages (from-to)318-322
Number of pages5
JournalJournal of Luminescence
Issue numberSPEC. ISS.
Publication statusPublished - 2006 Jul
Externally publishedYes


  • Dephasing
  • Four-wave mixing
  • Optical anisotropy
  • Quantum dot

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • General Chemistry
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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