No abstract

We observe multiple excitonic optical Rabi oscillations in a semiconductor quantum well. Up to eight oscillation periods of the heavy-hole exciton density on a subpicosecond time scale are observed. An approximate linear dependence of the oscillation frequency on the light field amplitude is established. The experiment is based on a two-color detection scheme which allows for the observation of the heavy-hole exciton density via transmission changes at the light-hole exciton. The observations are in good agreement with theoretical computations based on multiband semiconductor Bloch equations.[S0031-9007(99)08665-2]

We present results from solutions of the semiconductor Kadanoff‐Baym equations (full two‐time semiconductor Bloch equations) with self‐energies in quasistatic Born approximation, for GaAs single quantum wells. We concentrate on memory and correlation effects under fs‐pulse excitation conditions. A remarkable feature is the observed kinetic energy increase which is due to the build‐up of correlations among the generated carriers. We demonstrate that the two‐time approach is (i) very well suited to study correlation phenomena both on short and long times, thereby avoiding well‐known problems of one‐time kinetic equations, and (ii) that it is becoming practical with the use of efficient integration techniques.