Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 59: SKM Symposium: Semiconductor Nanophotonics - Quantum Optics and Devices (SYNP)
HL 59.3: Hauptvortrag
Mittwoch, 16. März 2011, 15:30–16:00, TRE Ma
Coherent optoelectronic control of a single exciton qubit — •Artur Zrenner1, Steffen Michaelis de Vasconcellos1, Simon Gordon1, Dirk Mantei1, Wadim Quiring1, Mohannad Al-Hmoud1, Torsten Meier1, Max Bichler2, Andreas D. Wieck3, and Dirk Reuter3 — 1Universität Paderborn, D-33095 Paderborn — 2Walter Schottky Institut, Technische Universität München, D-85748 Garching — 3Ruhr-Universität Bochum, D-44780 Bochum
Due to their excellent coupling to light, excitons in semiconductor quantum dots are in particular interesting for the implementation of coherent optoelectronic devices. In our present contribution we present results on the coherent manipulation of an exciton by fast electric signals. The new scheme employs fixed optical clocking and a synchronous electric gate signal, which is designed to coherently control the phase of the exciton qubit. A first picosecond laser clock pulse turns thereby the qubit in a coherent superposition state. Afterwards, the phase of the qubit is manipulated by an electric signal, which is phase locked to the laser pulses. A second laser pulse and subsequent state projection by tunneling are used to analyze the quantum state after the coherent manipulation. Using this protocol, we are able to achieve a quantum phase shift of up to pi by varying the electric signal. To verify the experimental data we performed calculations based on the optical Bloch equations. Such voltage controlled qubit manipulations seem to be essential for new types of scalable optoelectronic quantum phase gates and novel applications in the field of coherent optoelectronics.