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Department of Physics
Artistic View of the Bloch sphere © Harald Ritsch | Innsbruck

Two-color excitation schemes analyzed in the dressed states

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Sketch of the dressed states to illustrate the contents of the paper © Thomas Bracht | TU Dortmund
Evolution of the dressed-state energies in a three-level system

About a year ago, we proposed the Swing-UP of quantum EmitteR (SUPER) scheme to invert a two-level system. The novelty about the SUPER scheme is that it uses two red-detuned pulses, which alone would not lead to an inversion because of their detuning. To understand this puzzling effect, in this paper we present an analysis of the SUPER scheme in the dressed-state basis. Dressed states are the eigenstates of the coupled quantum dot-light system. We show that while one laser pulse sets the dressed states, the second laser pulse drives transitions between them, which in the bare states leads to the inversion. We also connect our results to dichromatic excitation schemes, where one laser pulse is red and one pulse is blue detuned. Our results give better insights into the SUPER mechanism, such that we can also extend it to more complicated systems.

The paper results from a collaboration with the theoretical group from Martin Axt from Bayreuth, and the Photonics group from Innsbruck.

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The campus of TU Dort­mund University is located close to interstate junction Dort­mund West, where the Sauerlandlinie A 45 (Frankfurt-Dort­mund) crosses the Ruhrschnellweg B 1 / A 40. The best interstate exit to take from A 45 is “Dort­mund-Eichlinghofen” (closer to South Campus), and from B 1 / A 40 “Dort­mund-Dorstfeld” (closer to North Campus). Signs for the uni­ver­si­ty are located at both exits. Also, there is a new exit before you pass over the B 1-bridge leading into Dort­mund.

To get from North Campus to South Campus by car, there is the connection via Vogelpothsweg/Baroper Straße. We recommend you leave your car on one of the parking lots at North Campus and use the H-Bahn (suspended monorail system), which conveniently connects the two campuses.

TU Dort­mund University has its own train station (“Dort­mund Uni­ver­si­tät”). From there, suburban trains (S-Bahn) leave for Dort­mund main station (“Dort­mund Hauptbahnhof”) and Düsseldorf main station via the “Düsseldorf Airport Train Station” (take S-Bahn number 1, which leaves every 20 or 30 minutes). The uni­ver­si­ty is easily reached from Bochum, Essen, Mülheim an der Ruhr and Duisburg.

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