Fingerprints of spatial charge transfer in Quantum Cascade Lasers

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We show that mid-infrared transmission spectroscopy of a quantum cascade laser provides clear-cut information on changes in charge location at different bias. Theoretical simulations of the evolution of the gain/absorption spectrum for a lambda~7.4 µm InGaAs/AlInAs/InP quantum cascade laser have been compared with the experimental findings. Transfer of electrons between the ground states in the active region and the states in the injector goes hand in hand with a decrease of discrete intersubband absorption peaks and an increase of broad, high-energy absorption toward the continuum delocalized states above the barriers.


  • Rikard Nelander
  • Andreas Wacker
  • M. F. Pereira
  • D. G. Revin
  • M. R. Soulby
  • L. R. Wilson
  • J. W. Cockburn
  • A. B. Krysa
  • J. S. Roberts
  • R. J. Airey
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Condensed Matter Physics
Original languageEnglish
Pages (from-to)113104-1-113104-5
JournalJournal of Applied Physics
Publication statusPublished - 2007
Publication categoryResearch

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