Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Quantum Dots and Wires, Optical Properties II: Single Photon Sources

HL 24.5: Vortrag

Dienstag, 23. März 2010, 12:30–12:45, H17

Coherent optoelectronic manipulation of single excitons — •Steffen Michaelis de Vasconcellos1, Simon Gordon1, Dirk Mantei1, Max Bichler2, Torsten Meier1, and Artur Zrenner11CeOPP, Universität Paderborn, Paderborn, Germany — 2WSI, TU München, Garching, Germany

The coherent state manipulation of single quantum systems is a fundamental requirement for the implementation of quantum information devices. As recently shown, excitons in semiconductor quantum dots are an interesting qubit implementation for coherent optoelectronic devices, especially due to their excellent control by ultrafast laser pulses.

In our contribution, we present the coherent manipulation of an exciton in a single QD by electric signals. The new scheme employs a fixed optical clock signal and a synchronous electric gate signal, which is applied to a single QD photodiode and controls the coherent manipulation of the exciton qubit. A first picosecond laser pulse turns the qubit in a coherent superposition state. Afterwards, the phase of the qubit is manipulated by applying a 2.4 GHz electric signal, which is phase locked to the laser pulses. A second laser pulse is used to analyze the quantum state after the coherent manipulation. We are able to achieve a quantum phase shift of π by varying the electric phase of the 2.4 GHz signal. To verify the experimental data, we performed theoretical calculations based on the optical Bloch equations. These show a very good agreement with the experimental data.

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