Parts | Days | Selection | Search | Downloads | Help
HL: Halbleiterphysik
HL 19: Hauptvortrag Zrenner
HL 19.1: Invited Talk
Saturday, March 5, 2005, 09:45–10:30, TU P270
Manipulations of a qubit in a semiconductor quantum dot — •Artur Zrenner1, Stefan Stufler1, Patrick Ester1 und Max Bichler2 — 1Universität Paderborn, Warburger Str. 100, D-33098 Paderborn — 2Walter Schottky Institut, Technische Universität München, Am Coulombwall, D-85748 Garching
Semiconductor quantum dots are zero-dimensional model systems with excellent optic and electric properties. In optical experiments on single self-assembled InGaAs quantum dots the excitonic ground state transition appears as an extremely narrow resonance of only a few µeV width. The resonant interaction with cw laser fields can be studied in detail by photocurrent spectroscopy, revealing the effects of nonlinear absorption and power broadening of the line width, as expected for a genuine two-level system. For the case of pulsed laser fields and in the absence of decoherence, the two-level system represents a qubit. Excitations with ps laser pulses result in qubit rotations, which can be evidenced in a quantitative way as Rabi oscillations in photocurrent experiments. Double pulse experiments further allow us to infer important system parameters like the decoherence time and the excitonic fine structure of the underlying two level system.