Homogeneous broadening and excitation-induced dephasing of intersubband transitions in a quasi-two-dimensional electron gas

Robert A. Kaindl, Klaus Reimann, Michael Woerner, Thomas Elsaesser, R. Hey, K. H. Ploog

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

The irreversible decay of coherent intersubband polarizations in n-type modulation-doped GaAs/AlxGa1-xAs quantum wells is studied by femtosecond time-integrated and time-resolved four-wave mixing. We provide the first direct evidence for predominant homogeneous broadening of intersubband resonances by intraband electron-electron scattering. Even at a low electron concentration of 5×1010 cm-2 the dephasing time T2=320 fs accounts fully for the 4 meV intersubband linewidth. For 6×1011 electrons/cm2 and strong excitation, athermal electron distributions show enhanced dephasing rates.

Original languageEnglish (US)
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume63
Issue number16
DOIs
StatePublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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