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Ultrafast Coherent Carrier Control in Quantum Wells
Author(s) -
Baumberg J. J.,
Heberle A. P.,
Köhler K.,
Kavokin A. V.
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<9::aid-pssb9>3.0.co;2-6
Subject(s) - ultrashort pulse , coherence (philosophical gambling strategy) , coherent control , quantum well , physics , quantum beats , quantum interference , polariton , optics , coherence time , interference (communication) , coherent backscattering , quantum , exponential decay , quantum mechanics , laser , scattering , telecommunications , channel (broadcasting) , computer science
A fast scanning ultrafast phase‐dependent reflectivity technique is used to measure the coherent properties of multiple quantum wells at carrier densities below 10 8 cm —2 . Signal to noise ratios in the reflected intensity >80 dB can be achieved allowing underlying coherences to be measured at time delays beyond 30 ps. An unexpected 1.5 ps rise time of the coherence is resolved before a non‐exponential decay and ascribed to interference of polaritons. By time‐resolving the pair of pulses reflected off the sample, a complete history of energy flow in the quantum wells can be identified. Both spontaneous and stimulated coherent reemission are observed in good agreement with models based on the Bloch equations.