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Basso Basset F, Rota MB, Schimpf C, Tedeschi D, Zeuner KD, Covre da Silva SF, Reindl M, Zwiller V, Jöns KD, Rastelli A, Trotta R. Entanglement Swapping with Photons Generated on Demand by a Quantum Dot. Phys Rev Lett 2019; 123:160501. [PMID: 31702339 DOI: 10.1103/physrevlett.123.160501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Indexed: 06/10/2023]
Abstract
Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve state-of-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.
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Affiliation(s)
- F Basso Basset
- Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
| | - M B Rota
- Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
| | - C Schimpf
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, 4040 Linz, Austria
| | - D Tedeschi
- Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
| | - K D Zeuner
- Department of Applied Physics, Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - S F Covre da Silva
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, 4040 Linz, Austria
| | - M Reindl
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, 4040 Linz, Austria
| | - V Zwiller
- Department of Applied Physics, Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - K D Jöns
- Department of Applied Physics, Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - A Rastelli
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, 4040 Linz, Austria
| | - R Trotta
- Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
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Fognini A, Ahmadi A, Daley SJ, Reimer ME, Zwiller V. Universal fine-structure eraser for quantum dots. Opt Express 2018; 26:24487-24496. [PMID: 30469565 DOI: 10.1364/oe.26.024487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/13/2018] [Indexed: 06/09/2023]
Abstract
We analyze the degree of entanglement measurable from a quantum dot via the biexciton-exciton cascade as a function of the exciton fine-structure splitting and the detection time resolution. We show that the time-energy uncertainty relation provides means to measure a high entanglement even in presence of a finite fine-structure splitting when a detection system with high temporal resolution is employed. Still, in many applications it would be beneficial if the fine-structure splitting could be compensated to zero. To solve this problem, we propose an all-optical approach with rotating waveplates to erase this fine-structure splitting completely which should allow obtaining a high degree of entanglement with near-unity efficiency. Our optical approach is possible with current technology and is also compatible with any quantum dot showing fine-structure splitting. This bears the advantage that for example the fine-structure splitting of quantum dots in nanowires and micropillars can be directly compensated without the need for further sample processing.
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Abstract
In semiconducting nanowires, both zinc blende and wurtzite crystal structures can coexist. The band structure difference between the two structures can lead to charge confinement. Here we fabricate and study single quantum dot devices defined solely by crystal phase in a chemically homogeneous nanowire and observe single photon generation. More generally, our results show that this type of carrier confinement represents a novel degree of freedom in device design at the nanoscale.
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Affiliation(s)
- N Akopian
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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Ding F, Singh R, Plumhof JD, Zander T, Krápek V, Chen YH, Benyoucef M, Zwiller V, Dörr K, Bester G, Rastelli A, Schmidt OG. Tuning the exciton binding energies in single self-assembled InGaAs/GaAs quantum dots by piezoelectric-induced biaxial stress. Phys Rev Lett 2010; 104:067405. [PMID: 20366855 DOI: 10.1103/physrevlett.104.067405] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Indexed: 05/29/2023]
Abstract
We study the effect of an external biaxial stress on the light emission of single InGaAs/GaAs(001) quantum dots placed onto piezoelectric actuators. With increasing compression, the emission blueshifts and the binding energies of the positive trion (X+) and biexciton (XX) relative to the neutral exciton (X) show a monotonic increase. This phenomenon is mainly ascribed to changes in electron and hole localization and it provides a robust method to achieve color coincidence in the emission of X and XX, which is a prerequisite for the possible generation of entangled photon pairs via the recently proposed "time reordering" scheme.
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Affiliation(s)
- F Ding
- Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany.
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Sasakura H, Kumano H, Suemune I, Motohisa J, Kobayashi Y, Kouwen MV, Tomioka K, Fukui T, Akopian N, Zwiller V. Exciton coherence in clean single InP/InAsP/InP nanowire quantum dots emitting in infra-red measured by Fourier spectroscopy. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/193/1/012132] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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