Coherent nonlinear dynamics of intersubband excitations in a two-dimensional electron gas

M. Woerner, R. A. Kaindl, F. Eickemeyer, K. Reimann, T. Elsaesser, A. M. Weiner, R. Hey, K. H. Ploog

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Femtosecond midinfrared four-wave mixing is used to study the ultrafast dynamics of coherent intersubband polarizations in n-type modulation-doped GaAs/AlGaAs quantum wells. Time-integrated four-wave mixing yields a dephasing time of T2 = 320 fs, independent of excitation density. Time-resolved four-wave mixing unambiguously shows that the intersubband transition is purely homogeneously broadened by intraband Coulomb scattering within the low-density (n = 5 × 1010 cm-2) electron plasma. The nonlinear propagation of tailored midinfrared pulses is studied by electro-optic sampling, which allows direct time-resolved measurements of the electric field transients. Excitation pulses of only 1 pJ energy are needed to observe partial Rabi flops of up to 60° in the Bloch sphere.

Original languageEnglish (US)
Pages (from-to)244-247
Number of pages4
JournalPhysica B: Condensed Matter
Issue number1-4
StatePublished - Mar 2002
Externally publishedYes


  • Coherent polarization
  • Intersubband transitions
  • Quantum wells

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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