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Strong Dephasing in a Laser Excited Semiconductor Due to Carrier–Plasmon Scattering
Author(s) -
Manzke G.,
Moldzio U.,
Henneberger K.
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(199708)202:2<961::aid-pssb961>3.0.co;2-c
Subject(s) - dephasing , plasmon , excited state , semiconductor , scattering , laser , optoelectronics , materials science , physics , atomic physics , optics , condensed matter physics
The generation of a dense electron–hole plasma by an intense short laser pulse is investigated by solving the semiconductor Bloch equations. The kinetics of plasmons on a sub‐ps time scale is demonstrated to be important for the relaxation and dephasing behaviour in comparison to a simple static treatment of screening under the considered excitation conditions with carrier densities in the range of 10 17 to 10 18 cm —3 for GaAs. Strong dephasing is found particularly for the early stage of the excitation, when the pulse is rising. However, peak scattering with dephasing times below 10 fs as shown by Scott et al. [1] to be possible for strongly peaked nonequilibrium carrier distributions is prevented by the fast relaxation of the excitation peak and the fast filling of carrier distributions at small wavenumbers. Scattering of the coherent polarization at the carriers reduces the decay of polarization in comparison with the dephasing‐rate approximation, where it is generated by carrier–carrier scattering only. Moreover coherent scattering decreases the generation rate of carriers in the presence of the pulse resulting in a strongly reduced final carrier density.