| 1. |
- Descamps, Thomas, et al.
(författare)
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Dynamic Strain Modulation of a Nanowire Quantum Dot Compatible with a Thin-Film Lithium Niobate Photonic Platform
- 2023
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 10:10, s. 3691-3699
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Tidskriftsartikel (refereegranskat)abstract
- The integration of indistinguishable single photon sources in photonic circuits is a major prerequisite for on-chip quantum applications. Among the various high-quality sources, nanowire quantum dots can be efficiently coupled to optical waveguides because of their preferred emission direction along their growth direction. However, local tuning of the emission properties remains challenging. In this work, we transfer a nanowire quantum dot onto a bulk lithium niobate substrate and show that its emission can be dynamically tuned by acousto-optical coupling with surface acoustic waves. The purity of the single photon source is preserved during the strain modulation. We further demonstrate that the transduction is maintained even with a SiO2 encapsulation layer deposited on top of the nanowire acting as the cladding of a photonic circuit. Based on these experimental findings and numerical simulations, we introduce a device architecture consisting of a nanowire quantum dot efficiently coupled to a thin-film lithium niobate rib waveguide and strain-tunable by surface acoustic waves.
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| 2. |
- Elshaari, Ali W., et al.
(författare)
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On-chip single photon filtering and multiplexing in hybrid quantum photonic circuits
- 2017
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Quantum light plays a pivotal role in modern science and future photonic applications. Since the advent of integrated quantum nanophotonics different material platforms based on III-V nanostructures-, colour centers-, and nonlinear waveguides as on-chip light sources have been investigated. Each platform has unique advantages and limitations; however, all implementations face major challenges with filtering of individual quantum states, scalable integration, deterministic multiplexing of selected quantum emitters, and on-chip excitation suppression. Here we overcome all of these challenges with a hybrid and scalable approach, where single III-V quantum emitters are positioned and deterministically integrated in a complementary metal-oxide-semiconductor-compatible photonic circuit. We demonstrate reconfigurable on-chip single-photon filtering and wavelength division multiplexing with a foot print one million times smaller than similar table-top approaches, while offering excitation suppression of more than 95 dB and efficient routing of single photons over a bandwidth of 40 nm. Our work marks an important step to harvest quantum optical technologies' full potential.
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| 3. |
- Elshaari, Ali W., et al.
(författare)
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Strain-Tunable Quantum Integrated Photonics
- 2018
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 18:12, s. 7969-7976
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor quantum dots are crucial parts of the photonic quantum technology toolbox because they show excellent single-photon emission properties in addition to their potential as solid-state qubits. Recently, there has been an increasing effort to deterministically integrate single semiconductor quantum dots into complex photonic circuits. Despite rapid progress in the field, it remains challenging to manipulate the optical properties of waveguide-integrated quantum emitters in a deterministic, reversible, and nonintrusive manner. Here we demonstrate a new class of hybrid quantum photonic circuits combining III V semiconductors, silicon nitride, and piezoelectric crystals. Using a combination of bottom-up, top-down, and nanomanipulation techniques, we realize strain tuning of a selected, waveguide-integrated, quantum emitter and a planar integrated optical resonator. Our findings are an important step toward realizing reconfigurable quantum-integrated photonics, with full control over the quantum sources and the photonic circuit.
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| 4. |
- Gao, Jun, et al.
(författare)
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Scalable Generation and Detection of on-Demand W States in Nanophotonic Circuits
- 2023
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 23:11, s. 5350-5357
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Tidskriftsartikel (refereegranskat)abstract
- Quantum physics phenomena,entanglement and coherence,are crucialfor quantum information protocols, but understanding these in systemswith more than two parts is challenging due to increasing complexity.The W state, a multipartite entangled state, is notable for its robustnessand benefits in quantum communication. Here, we generate eight-modeon-demand single-photon W states, using nanowire quantum dots anda silicon nitride photonic chip. We demonstrate a reliable and scalabletechnique for reconstructing the W state in photonic circuits usingFourier and real-space imaging, supported by the Gerchberg-Saxtonphase retrieval algorithm. Additionally, we utilize an entanglementwitness to distinguish between mixed and entangled states, therebyaffirming the entangled nature of our generated state. The study providesa new imaging approach of assessing multipartite entanglement in Wstates, paving the way for further progress in image processing andFourier-space analysis techniques for complex quantum systems.
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| 5. |
- Gourgues, Ronan, et al.
(författare)
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Controlled integration of selected detectors and emitters in photonic integrated circuits
- 2019
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Ingår i: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 27:3, s. 3710-3716
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Tidskriftsartikel (refereegranskat)abstract
- Integration of superconducting nanowire single-photon detectors and quantum sources with photonic waveguides is crucial for realizing advanced quantum integrated circuits. However, scalability is hindered by stringent requirements on high-performance detectors. Here we overcome the yield limitation by controlled coupling of photonic channels to pre-selected detectors based on measuring critical current, timing resolution, and detection efficiency. As a proof of concept of our approach, we demonstrate a hybrid on-chip full-transceiver consisting of a deterministically integrated detector coupled to a selected nanowire quantum dot through a filtering circuit made of a silicon nitride waveguide and a ring resonator filter, delivering 100 dB suppression of the excitation laser. In addition, we perform extensive testing of the detectors before and after integration in the photonic circuit and show that the high performance of the superconducting nanowire detectors, including timing jitter down to 23 +/- 3 ps, is maintained. Our approach is fully compatible with wafer-level automated testing in a cleanroom environment.
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| 6. |
- Haffouz, Sofiane, et al.
(författare)
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Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires : The Role of the Photonic Waveguide
- 2018
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Ingår i: Nano letters (Print). - : AMER CHEMICAL SOC. - 1530-6984 .- 1530-6992. ; 18:5, s. 3047-3052
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Tidskriftsartikel (refereegranskat)abstract
- We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.
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| 7. |
- Jöns, Klaus D., et al.
(författare)
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Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Global, secure quantum channels will require efficient distribution of entangled photons. Long distance, low-loss interconnects can only be realized using photons as quantum information carriers. However, a quantum light source combining both high qubit fidelity and on-demand bright emission has proven elusive. Here, we show a bright photonic nanostructure generating polarization-entangled photon pairs that strongly violates Bell's inequality. A highly symmetric InAsP quantum dot generating entangled photons is encapsulated in a tapered nanowire waveguide to ensure directional emission and efficient light extraction. We collect similar to 200 kHz entangled photon pairs at the first lens under 80 MHz pulsed excitation, which is a 20 times enhancement as compared to a bare quantum dot without a photonic nanostructure. The performed Bell test using the Clauser-Horne-Shimony-Holt inequality reveals a clear violation (S-CHSH > 2) by up to 9.3 standard deviations. By using a novel quasi-resonant excitation scheme at the wurtzite InP nanowire resonance to reduce multi-photon emission, the entanglement fidelity (F = 0.817 +/- 0.002) is further enhanced without temporal post-selection, allowing for the violation of Bell's inequality in the rectilinear-circular basis by 25 standard deviations. Our results on nanowire-based quantum light sources highlight their potential application in secure data communication utilizing measurement-device-independent quantum key distribution and quantum repeater protocols.
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| 8. |
- Lagoudakis, Konstantinos G., et al.
(författare)
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Initialization of a spin qubit in a site-controlled nanowire quantum dot
- 2016
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Ingår i: New Journal of Physics. - : Institute of Physics (IOP). - 1367-2630. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- A fault-tolerant quantum repeater or quantum computer using solid-state spin-based quantum bits will likely require a physical implementation with many spins arranged in a grid. Self-assembled quantum dots (QDs) have been established as attractive candidates for building spin-based quantum information processing devices, but such QDs are randomly positioned, which makes them unsuitable for constructing large-scale processors. Recent efforts have shown that QDs embedded in nanowires can be deterministically positioned in regular arrays, can store single charges, and have excellent optical properties, but so far there have been no demonstrations of spin qubit operations using nanowire QDs. Here we demonstrate optical pumping of individual spins trapped in site-controlled nanowire QDs, resulting in high-fidelity spin-qubit initialization. This represents the next step towards establishing spins in nanowire QDs as quantum memories suitable for use in a large-scale, fault-tolerant quantum computer or repeater based on all-optical control of the spin qubits.
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| 9. |
- Pennacchietti, Matteo, et al.
(författare)
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Oscillating photonic Bell state from a semiconductor quantum dot for quantum key distribution
- 2024
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Ingår i: Communications Physics. - : Springer Nature. - 2399-3650. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- An on-demand source of bright entangled photon pairs is desirable for quantum key distribution (QKD) and quantum repeaters. The leading candidate to generate such pairs is based on spontaneous parametric down-conversion (SPDC) in non-linear crystals. However, its pair extraction efficiency is limited to 0.1% when operating at near-unity fidelity due to multiphoton emission at high brightness. Quantum dots in photonic nanostructures can in principle overcome this limit, but the devices with high entanglement fidelity (99%) have low pair extraction efficiency (0.01%). Here, we show a measured peak entanglement fidelity of 97.5% ± 0.8% and pair extraction efficiency of 0.65% from an InAsP quantum dot in an InP photonic nanowire waveguide. We show that the generated oscillating two-photon Bell state can establish a secure key for peer-to-peer QKD. Using our time-resolved QKD scheme alleviates the need to remove the quantum dot energy splitting of the intermediate exciton states in the biexciton-exciton cascade.
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| 10. |
- Reimer, Michael E., et al.
(författare)
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High efficiency entangled photon sources and single photon detectors based-on semiconductor nanowires
- 2019
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Ingår i: The 10th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2019. - : META Conference. ; , s. 1132-
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Konferensbidrag (refereegranskat)abstract
- Semiconductor nanowires offer a powerful platform for engineering light at the nanoscale by controlling their size and shape in order to guide light efficiently and minimize undesired reflections. In this work we have shaped the nanowires with a unique tapering to realize bright quantum dot based entangled photon sources and high efficiency single photon detectors with high speed and timing resolution over an unprecedented bandwidth.
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