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Discrimination between the Interband and Intraband Coherences in Pump–Probe Signals from Semiconductors
Author(s) -
Bartels G.,
Stahl A.
Publication year - 1998
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/(sici)1521-3951(199803)206:1<325::aid-pssb325>3.0.co;2-0
Subject(s) - dephasing , biexciton , physics , exciton , excitation , density matrix , amplitude , observable , condensed matter physics , quantum mechanics , quantum , atomic physics
We discuss coherent heavy‐hole light‐hole quantum beats in transient pump–probe signals from a homogeneous GaAs quantum well in the low density regime using a microscopic density matrix theory. A key feature of our theory is the inclusion of higher order correlation functions like the biexciton transition amplitude and the exciton density comprising both interband and intraband character. Our calculations show that the heavy‐hole light‐hole quantum beats are dominated by the longer living intraband coherent contributions for most excitation conditions. In the special case when both pump and probe are linearly polarized, forming an angle of 45°, the coherent signature is exclusively caused by the otherwise small contributions of the biexciton transition amplitude, i.e. an interband coherent correlation function. In this way the different interband and intraband dephasing times should be observable separately in PP signals, depending on the excitation conditions.