Accessing the dark exciton spin in deterministic quantum-dot microlenses

The dark exciton state in semiconductor quantum dots constitutes a long-lived solid-state qubit which has the potential to play an important role in implementations of solid-state based quantum information architectures. In this work, we exploit deterministically fabricated QD microlenses with enhan...

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Published inarXiv.org
Main Authors Heindel, Tobias, Thoma, Alexander, Schwartz, Ido, Schmidgall, Emma R, Gantz, Liron, Cogan, Dan, Max Strau\ss, Schnauber, Peter, Gschrey, Manuel, Schulze, Jan-Hindrik, Strittmatter, Andre, Rodt, Sven, Gershoni, David, Reitzenstein, Stephan
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 04.08.2017
Subjects
Computer architecture
Data processing
Eigenvectors
Excitons
Microlenses
Photonics
Physics - Mesoscale and Nanoscale Physics
Physics - Quantum Physics
Precession
Quantum dots
Quantum phenomena
Quantum theory
Qubits (quantum computing)
Solid state
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Summary:The dark exciton state in semiconductor quantum dots constitutes a long-lived solid-state qubit which has the potential to play an important role in implementations of solid-state based quantum information architectures. In this work, we exploit deterministically fabricated QD microlenses with enhanced photon extraction, to optically prepare and readout the dark exciton spin and observe its coherent precession. The optical access to the dark exciton is provided via spin-blockaded metastable biexciton states acting as heralding state, which are identified deploying polarization-sensitive spectroscopy as well as time-resolved photon cross-correlation experiments. Our experiments reveal a spin-precession period of the dark exciton of \((0.82\pm0.01)\,\)ns corresponding to a fine-structure splitting of \((5.0\pm0.7)\,\mu\)eV between its eigenstates \(\left|\uparrow\Uparrow\pm\downarrow\Downarrow\right\rangle\). By exploiting microlenses deterministically fabricated above pre-selected QDs, our work demonstrates the possibility to scale up implementations of quantum information processing schemes using the QD-confined dark exciton spin qubit, such as the generation of photonic cluster states or the realization of a solid-state-based quantum memory.
ISSN:2331-8422
DOI:10.48550/arxiv.1706.05164