Premium
Quantum Beats and Exciton Coherence in Time‐Resolved Resonant Light Scattering
Author(s) -
Stolz H.
Publication year - 1992
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.2221730111
Subject(s) - dephasing , quantum beats , exciton , relaxation (psychology) , coherence (philosophical gambling strategy) , scattering , raman scattering , atomic physics , inelastic scattering , physics , light scattering , excitation , polariton , condensed matter physics , raman spectroscopy , optics , quantum mechanics , excited state , psychology , social psychology
The time‐resolved resonant light scattering spectrum following short pulse excitation provides information on the various inelastic (energy relaxation) and elastic (phase relaxation) relaxation processes of an exciton system. Taking properly the implications of the measurement process into account this can be exploited to discriminate between Raman scattering processes, proceeding without loss of coherence, and hot luminescence, occurring after phase relaxation. The coherent nature of the states can be directly revealed by quantum beats in the time‐dependent scattering spectrum if the resonant states are energetically split. Such experiments are presented for bound excitons in CdS and the lowest exciton‐polariton in Cu 2 O. These measurements allow to deduce refined magneto‐optical parameters due to the high energy resolution of this method. The exciton dephasing times found are surprisingly long (up to 1 ns) and determined by energy relaxation due to phonon scattering. Pure dephasing due to elastic scattering gives only a minor contribution.