title: Signatures of Quantum Coherences in Rydberg Excitons.
abstract: Coherent optical control of individual particles has been demonstrated both for atoms and semiconductor quantum dots. Here we demonstrate the emergence of quantum coherent effects in semiconductor Rydberg excitons in bulk Cu_{2}O. Because of the spectral proximity between two adjacent Rydberg exciton states, a single-frequency laser may pump both resonances with little dissipation from the detuning. As a consequence, additional resonances appear in the absorption spectrum that correspond to dressed states consisting of two Rydberg exciton levels coupled to the excitonic vacuum, forming a V-type three-level system, but driven only by one laser light source. We show that the level of pure dephasing in this system is extremely low. These observations are a crucial step towards coherently controlled quantum technologies in a bulk semiconductor.
authors.affiliation: Institut für Physik, Universität Rostock, Albert-Einstein-Strasse 23, D-18059 Rostock, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Grünwald
authors.affiliation: Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Aßmann
authors.affiliation: Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Heckötter
authors.affiliation: Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Fröhlich
authors.affiliation: Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bayer
authors.affiliation: Institut für Physik, Universität Rostock, Albert-Einstein-Strasse 23, D-18059 Rostock, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Stolz
authors.affiliation: Institut für Physik, Universität Rostock, Albert-Einstein-Strasse 23, D-18059 Rostock, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Scheel