Coherent dynamics of continuum and excitonic states in quantum confined systems

We present an experimental study on the coherent dynamics of charge carriers in semiconductor heterostructures, i.e. Bloch oscillations in superlattices and intervalence band quantum beats in single quantum wells. With a combination of four-wave mixing and electron-optic sampling we are able to compare the dynamics of the optical conduction-valence band (interband) coherence with that of the far-infrared intraconduction band and intervalence band coherences. The dephasing times of the latter coherences are observed to be significantly longer than that of the interband coherence.