Open AccessMechanism of optical polarization dephasing in bulk GaAs and multiple quantum wells
Author(s) -
Li Deng,
Qian Shou,
Yexin Liu,
Haichao Zhang,
Tianshu Lai,
Lin Wang
Publication year - 2004
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.53.640
Subject(s) - dephasing , quantum well , polarization (electrochemistry) , condensed matter physics , scattering , density matrix , degenerate energy levels , quantum beats , physics , materials science , excitation , four wave mixing , atomic physics , nonlinear optics , quantum , optics , chemistry , laser , quantum mechanics
The optical polarization dephasing times in bulk GaAs and GaAs/Al0.3Ga0.7As quantum wells at room temperature are measured using time-resolved degenerate-four-wave mixing (DFWM). Under the conditions of excitation pulse central wavelength of 785nm and carrier density of 1011cm-2, the dephasing times of 28 and 46 fs for bulk GaAs and multiple quantum wells, respectively, are measured. Because the carrier-carrier scattering rate in quantum wells is reduced due to the confinement of the carrier behaviorthe dephasing time of the quantum wells is longer than that of bulk. The dependence of the DFWM signal on the intensity and the polarization of the incident pulses is evaluated by a theoretical model of third-order nonlinear density matrix.