We study the evolution of an exciton confined in a quantum dot adiabatically controlled by a frequency-swept (chirped) laser pulse in the presence of carrier-phonon coupling. We focus on the dynamics induced by a linearly polarized beam and analyze the decoherence due to phonon-assisted biexciton generation. We show that if the biexciton state is shifted down by a few meV, as is typically the case, then the resulting decoherence is strong even at low temperatures. As a result, efficient state preparation is restricted to a small parameter area corresponding to low temperatures, positive chirps, and moderate pulse areas.

• Received 10 September 2012

DOI:https://doi.org/10.1103/PhysRevB.86.235301