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Main Title: Accessing the dark exciton spin in deterministic quantum-dot microlenses
Author(s): Heindel, Tobias
Thoma, Alexander
Schwartz, Ido
Schmidgall, Emma R.
Gantz, Liron
Cogan, Dan
Strauß, Max
Schnauber, Peter
Gschrey, Manuel
Schulze, Jan-Hindrik
Strittmatter, Andre
Rodt, Sven
Gershoni, David
Reitzenstein, Stephan
Type: Article
Language Code: en
Abstract: The dark exciton state in semiconductor quantum dots (QDs) 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 which promise enhanced photon extraction, to optically prepare and read out 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 states, which are identified by 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 ± 0.01) ns corresponding to a fine-structure splitting of (5.0 ± 0.7) μeV between its eigenstates ||↑⇑±↓⇓⟩. 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.
Issue Date: 2017
Date Available: 19-Jan-2018
DDC Class: 530 Physik
Subject(s): excitons
quantum dots
quantum computing
Sponsor/Funder: DFG, TH 662/19-1, Open Access Publizieren 2017 - 2018 / Technische Universität Berlin
Journal Title: APL photonics
Publisher: AIP Publishing
Publisher Place: Melville, NY
Volume: 2
Issue: 12
Article Number: 121303
Publisher DOI: 10.1063/1.5004147
ISSN: 2378-0967
Appears in Collections:AG Optoelektronik und Quantenbauelemente » Publications

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