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Relevance of Dephasing Processes for the Ultrafast Rise of Emission from Resonantly Created Excitons in Quantum Wells
Author(s) -
Haacke S.,
Hayes G.,
Taylor R. A.,
Deveaud B.,
Zimmermann R.,
BarJoseph I.
Publication year - 1997
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(199711)204:1<35::aid-pssb35>3.0.co;2-9
Subject(s) - dephasing , exciton , ultrashort pulse , physics , quantum well , relevance (law) , quantum , atomic physics , quantum mechanics , political science , laser , law
We present a comparative study of time‐integrated four‐wave‐mixing and femtosecond emission under resonant excitation on excitons in weakly disordered GaAs quantum wells. At highest exciton densities when dephasing dominates the spectral width (homogeneous broadening), we find that the rise time of the incoherent luminescence signal is given by T Iii 2/2. At lowest densities, optical coherence times approach the exciton radiative lifetime (15 to 20 ps). This confirms our previous result that coherent resonant Rayleigh scattering is responsible for the short rise time of the excitonic emission. We also show clear evidence for dephasing due to exciton–phonon interaction, as the rise time of the emission decreases dramatically when the sample temperature is increased.