Ultrafast transient gain in Ge/SiGe quantum wells

N. S. Köster, C. Lange, K. Kolata, S. Chatterjee, D. Chrastina, G. Isella, H. von Känel, H. Sigg, M. Schäfer, M. Kira, S. W. Koch

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The ultrafast carrier dynamics of Ge/SiGe quantum wells on Si substrate is investigated by pump-probe spectroscopy. Spectrally tunable 80 fs pulses emitted by an opto-parametric amplifier are used to excite the sample and a white-light supercontinuum generated from a 1 kHz Ti:sapphire regenerative amplifier system is used to probe the sample transmission. Pronounced nonequilibrium effects are observed in the relaxation dynamics. The pump energy dependence of these effects is discussed. If the sample is excited under close-to-resonant pumping conditions, transient gain is observed. The findings are explained using a microscopic many-body theory.

Original languageEnglish (US)
Pages (from-to)1109-1112
Number of pages4
JournalPhysica Status Solidi (C) Current Topics in Solid State Physics
Issue number4
StatePublished - Apr 1 2011


  • Carrier dynamics
  • Gain
  • Germanium
  • Pump-probe

ASJC Scopus subject areas

  • Condensed Matter Physics


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