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Phase relaxation of excitons in Zn 1− x Cd x Se/ZnSe multiple quantum well structures
Author(s) -
Weckendrup D.,
Saschek M.,
Neukirch U.,
Gutowski J.,
Ferreira S. O.,
Sitter H.
Publication year - 1995
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/pssb.2221880148
Subject(s) - dephasing , exciton , degenerate energy levels , biexciton , femtosecond , quantum beats , quantum well , relaxation (psychology) , condensed matter physics , four wave mixing , atomic physics , physics , molecular physics , chemistry , optics , nonlinear optics , laser , excited state , quantum mechanics , psychology , social psychology
The coherent dynamics of excitons in Zn 1− x Cd x ,Se/ZnSe multiple quantum wells measured by means of spectrally integrated as well as spectrally resolved transient degenerate four‐wave mixing are reported. When simultaneously exciting the heavy‐hole and light‐hole excitons by spectrally broad femtosecond pulses a quantum beating between heavy‐ and light‐hole excitons is observed. In spectrally resolved measurements an additional contribution from the 2s heavy‐hole exciton to the four‐wave‐mixing signal occurs which dephases very rapidly. By use of narrow‐band ps pulses the energy dependence of the dephasing rate in localized heavy‐hole exciton states is investigated. The dephasing times deduced from the experimental data increase for decreasing energy up to 4 ps in deeply localized states.