Ultrafast THz spectroscopy of excitons in multi-component carrier gases

R. A. Kaindl, M. A. Carnahan, D. Hägele, D. S. Chemla

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


We discuss time-resolved experiments that study photo-excited e-h pairs in GaAs quantum wells via their THz response. Resonant generation of excitons leads to characteristic THz spectra dominated by 1s-2p intra-excitonic transitions, which provide a direct density gauge. Fundamental differences between the intra-excitonic and free-carrier conductivity enable quantitative analysis of multicomponent e-h gases. We examine exciton ionization dynamics, where the exciton fraction approaches a quasi-equilibrium value in agreement with the Saha equation. A Saha model that takes into account thermal excitation of both heavy- and light-hole pairs is derived. Such experiments identify non-equilibrium phases of e-h gases and their underlying quasi-particle densities and dynamics.

Original languageEnglish (US)
Title of host publicationAdvances in Solid State Physics
EditorsRolf Haug
Number of pages12
StatePublished - 2008
Externally publishedYes

Publication series

NameAdvances in Solid State Physics
ISSN (Print)1438-4329

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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