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Active reset of a radiative cascade for superequilibrium entangled photon generation
Authors:
Jonathan R. A. Müller,
R. Mark Stevenson,
Joanna Skiba-Szymanska,
Ginny Shooter,
Jan Huwer,
Ian Farrer,
David A. Ritchie,
Andrew J. Shields
Abstract:
The generation rate of entangled photons emitted from cascaded few-level systems is intrinsically limited by the lifetime of the radiative transitions. Here, we overcome this limit for entangled photon pairs from quantum dots via a novel driving regime based on an active reset of the radiative cascade. We show theoretically and experimentally the driving regime to enable the generation of entangle…
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The generation rate of entangled photons emitted from cascaded few-level systems is intrinsically limited by the lifetime of the radiative transitions. Here, we overcome this limit for entangled photon pairs from quantum dots via a novel driving regime based on an active reset of the radiative cascade. We show theoretically and experimentally the driving regime to enable the generation of entangled photon pairs with higher fidelity and intensity compared to the optimum continuously driven equilibrium state. Finally, we electrically generate entangled photon pairs with a total fidelity of $(79.5 \pm 1.1)\%$ at a record clock rate of 1.15GHz.
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Submitted 17 January, 2020;
originally announced January 2020.
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A tuneable telecom-wavelength entangled light emitting diode
Authors:
Z. -H. Xiang,
J. Huwer,
J. Skiba-Szymanska,
R. M. Stevenson,
D. J. P. Ellis,
I. Farrer,
M. B. Ward,
D. A. Ritchie,
A. J. Shields
Abstract:
Entangled light emitting diodes based on semiconductor quantum dots are promising devices for security sensitive quantum network applications, thanks to their natural lack of multi photon-pair generation. Apart from telecom wavelength emission, network integrability of these sources ideally requires electrical operation for deployment in compact systems in the field. For multiplexing of entangled…
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Entangled light emitting diodes based on semiconductor quantum dots are promising devices for security sensitive quantum network applications, thanks to their natural lack of multi photon-pair generation. Apart from telecom wavelength emission, network integrability of these sources ideally requires electrical operation for deployment in compact systems in the field. For multiplexing of entangled photons with classical data traffic, emission in the telecom O-band and tuneability to the nearest wavelength channel in compliance with coarse wavelength division multiplexing standards (20 nm channel spacing) is highly desirable. Here we show the first fully electrically operated telecom entangled light emitting diode with wavelength tuneability of more than 25nm, deployed in an installed fiber network. With the source tuned to 1310.00 nm, we demonstrate multiplexing of true single entangled photons with classical data traffic and achieve entanglement fidelities above 95% on an installed fiber in a city.
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Submitted 26 September, 2019;
originally announced September 2019.
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A quantum light emitting diode for the standard telecom window around 1550 nm
Authors:
T. Müller,
J. Skiba-Szymanska,
A. Krysa,
J. Huwer,
M. Felle,
M. Anderson,
R. M. Stevenson,
J. Heffernan,
D. A. Ritchie,
A. J. Shields
Abstract:
For the development of long-distance quantum networks, sources of single photons and entangled photon pairs emitting in the low-loss wavelength region around 1550 nm are a crucial building block. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region with multiphoton events suppressed down to 0.11$\pm$0.…
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For the development of long-distance quantum networks, sources of single photons and entangled photon pairs emitting in the low-loss wavelength region around 1550 nm are a crucial building block. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region with multiphoton events suppressed down to 0.11$\pm$0.02. Using the biexciton cascade mechanism, they further produce entangled photons with a fidelity of 87$\pm$4%, sufficient for the application of one-way error correction protocols. The new material allows for entangled photon generation up to an operating temperature of 93 K, reaching a regime accessible by electric coolers. The quantum photon source can be directly integrated with existing long distance quantum communication and cryptography systems and provides a new material platform for developing future quantum network hardware.
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Submitted 10 October, 2017;
originally announced October 2017.
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Universal growth scheme for entanglement-ready quantum dots
Authors:
Joanna Skiba-Szymanska,
R. Mark Stevenson,
Christiana Varnava,
Martin Felle,
Jan Huwer,
Tina Müller,
Anthony J. Bennett,
James P. Lee,
Ian Farrer,
Andrey Krysa,
Peter Spencer,
Lucy E. Goff,
David A. Ritchie,
Jon Heffernan,
Andrew J. Shields
Abstract:
Efficient sources of individual pairs of entangled photons are required for quantum networks to operate using fibre optic infrastructure. Entangled light can be generated by quantum dots (QDs) with naturally small fine-structure-splitting (FSS) between exciton eigenstates. Moreover, QDs can be engineered to emit at standard telecom wavelengths. To achieve sufficient signal intensity for applicatio…
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Efficient sources of individual pairs of entangled photons are required for quantum networks to operate using fibre optic infrastructure. Entangled light can be generated by quantum dots (QDs) with naturally small fine-structure-splitting (FSS) between exciton eigenstates. Moreover, QDs can be engineered to emit at standard telecom wavelengths. To achieve sufficient signal intensity for applications, QDs have been incorporated into 1D optical microcavities. However, combining these properties in a single device has so far proved elusive. Here, we introduce a growth strategy to realise QDs with small FSS in the conventional telecom band, and within an optical cavity. Our approach employs droplet-epitaxy of InAs quantum dots on (001) substrates. We show the scheme improves the symmetry of the dots by 72%. Furthermore, our technique is universal, and produces low FSS QDs by molecular beam epitaxy on GaAs emitting at ~900nm, and metal-organic vapour phase epitaxy on InP emitting at 1550 nm, with mean FSS 4x smaller than for Stranski-Krastanow QDs.
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Submitted 27 September, 2016;
originally announced September 2016.
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Resonance fluorescence from a telecom-wavelength quantum dot
Authors:
R. Al-Khuzheyri,
A. C. Dada,
J. Huwer,
T. S. Santana,
J. Skiba- Szymanska,
M. Felle,
M. B. Ward,
R. M. Stevenson,
I. Farrer,
M. G. Tanner,
R. H. Hadfield,
D. A. Ritchie,
A. J. Shields,
B. D. Gerardot
Abstract:
We report on resonance fluorescence from a single quantum dot emitting at telecom wavelengths. We perform high-resolution spectroscopy and observe the Mollow triplet in the Rabi regime--a hallmark of resonance fluorescence. The measured resonance-fluorescence spectra allow us to rule out pure dephasing as a significant decoherence mechanism in these quantum dots. Combined with numerical simulation…
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We report on resonance fluorescence from a single quantum dot emitting at telecom wavelengths. We perform high-resolution spectroscopy and observe the Mollow triplet in the Rabi regime--a hallmark of resonance fluorescence. The measured resonance-fluorescence spectra allow us to rule out pure dephasing as a significant decoherence mechanism in these quantum dots. Combined with numerical simulations, the experimental results provide robust characterisation of charge noise in the environment of the quantum dot. Resonant control of the quantum dot opens up new possibilities for on-demand generation of indistinguishable single photons at telecom wavelengths as well as quantum optics experiments and direct manipulation of solid-state qubits in telecom-wavelength quantum dots.
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Submitted 7 July, 2016;
originally announced July 2016.