| 1. |
- Elshaari, Ali W., et al.
(författare)
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Deterministic Integration of hBN Emitter in Silicon Nitride Photonic Waveguide
- 2021
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Ingår i: Advanced Quantum Technologies. - : Wiley. - 2511-9044. ; 4:6, s. 2100032-
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid integration provides an important avenue for incorporating atom-like solid-state single-photon emitters into photonic platforms that possess no optically-active transitions. Hexagonal boron nitride (hBN) is particularly interesting quantum emitter for hybrid integration, as it provides a route for room-temperature quantum photonic technologies, coupled with its robustness and straightforward activation. Despite the recent progress of integrating hBN emitters in photonic waveguides, a deterministic, site-controlled process remains elusive. Here, the integration of selected hBN emitter in silicon nitride waveguide is demonstrated. A small misalignment angle of 4° is shown between the emission-dipole orientation and the waveguide propagation direction. The integrated emitter maintains high single-photon purity despite subsequent encapsulation and nanofabrication steps, delivering quantum light with zero delay second order correlation function (Formula presented.). The results provide an important step toward deterministic, large scale, quantum photonic circuits at room temperature using atom-like single-photon emitters.
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| 2. |
- Gyger, Samuel, et al.
(författare)
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On-chip integration of reconfigurable quantum photonics with superconducting photodetectors
- 2021
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Ingår i: 2021 Conference on Lasers and Electro-Optics, CLEO 2021 - Proceedings. - : Institute of Electrical and Electronics Engineers Inc..
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Konferensbidrag (refereegranskat)abstract
- Scaling up quantum optics experiments requires on-chip reconfigurable quantum photonics, but their integration with detectors is a challenge. We show microelectrome-chanical reconfiguration of photonic circuits with on-chip superconducting single-photon detectors and demonstrate key applications.
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| 3. |
- Gyger, Samuel, et al.
(författare)
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Reconfigurable photonics with on-chip single-photon detectors
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Integrated quantum photonics offers a promising path to scale up quantum optics experiments by miniaturizing and stabilizing complex laboratory setups. Central elements of quantum integrated photonics are quantum emitters, memories, detectors, and reconfigurable photonic circuits. In particular, integrated detectors not only offer optical readout but, when interfaced with reconfigurable circuits, allow feedback and adaptive control, crucial for deterministic quantum teleportation, training of neural networks, and stabilization of complex circuits. However, the heat generated by thermally reconfigurable photonics is incompatible with heat-sensitive superconducting single-photon detectors, and thus their on-chip co-integration remains elusive. Here we show low-power microelectromechanical reconfiguration of integrated photonic circuits interfaced with superconducting single-photon detectors on the same chip. We demonstrate three key functionalities for photonic quantum technologies: 28 dB high-extinction routing of classical and quantum light, 90 dB high-dynamic range single-photon detection, and stabilization of optical excitation over 12 dB power variation. Our platform enables heat-load free reconfigurable linear optics and adaptive control, critical for quantum state preparation and quantum logic in large-scale quantum photonics applications. Integrated photonics are promising to scale up quantum optics. Here the authors combine low-power microelectromechanical control and superconducting single-photon detectors on the same chip and demonstrate routing, high-dynamic-range detection, and power stabilization.
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| 4. |
- Lettner, Thomas, et al.
(författare)
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Strain-Controlled Quantum Dot Fine Structure for Entangled Photon Generation at 1550 nm
- 2021
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:24, s. 10501-10506
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Tidskriftsartikel (refereegranskat)abstract
- Entangled photon generation at 1550 nm in the telecom C-band is of critical importance as it enables the realization of quantum communication protocols over long distance using deployed telecommunication infrastructure. InAs epitaxial quantum dots have recently enabled on-demand generation of entangled photons in this wavelength range. However, time-dependent state evolution, caused by the fine-structure splitting, currently limits the fidelity to a specific entangled state. Here, we show fine-structure suppression for InAs quantum dots using micromachined piezoelectric actuators and demonstrate generation of highly entangled photons at 1550 nm. At the lowest fine-structure setting, we obtain a maximum fidelity of 90.0 +/- 2.7% (concurrence of 87.5 +/- 3.1%). The concurrence remains high also for moderate (weak) temporal filtering, with values close to 80% (50%), corresponding to 30% (80%) of collected photons, respectively. The presented fine-structure control opens the way for exploiting entangled photons from quantum dots in fiber-based quantum communication protocols.
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| 5. |
- Lin, Zuzeng, et al.
(författare)
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Efficient and versatile toolbox for analysis of time-tagged measurements
- 2021
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Ingår i: Journal of Instrumentation. - : IOP Publishing. - 1748-0221. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- Acquisition and analysis of time-tagged events is a ubiquitous tool in scientific and industrial applications. With increasing time resolution, number of input channels, and acquired events, the amount of data can be overwhelming for standard processing techniques. We developed the Extensible Time-tag Analyzer (ETA), a powerful and versatile, yet easy to use software to efficiently analyze and display time-tagged data. Our tool allows for flexible extraction of correlation from time-tagged data beyond start-stop measurements that were traditionally used. A combination of state diagrams and simple code snippets allows for analysis of arbitrary complexity while keeping computational efficiency high.
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| 6. |
- Versteegh, Marijn A. M., et al.
(författare)
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Giant Rydberg excitons in Cu2O probed by photoluminescence excitation spectroscopy
- 2021
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Ingår i: PHYSICAL REVIEW B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 104:24
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Tidskriftsartikel (refereegranskat)abstract
- Rydberg excitons are, with their ultrastrong mutual interactions, giant optical nonlinearities, and very high sensitivity to external fields, promising for applications in quantum sensing and nonlinear optics at the singlephoton level. To design quantum applications it is necessary to know how Rydberg excitons and other excited states relax to lower-lying exciton states. Here, we present photoluminescence excitation spectroscopy as a method to probe transition probabilities from various excitonic states in cuprous oxide. We show giant Rydberg excitons at T = 38 mK with principal quantum numbers up to n = 30, corresponding to a calculated diameter of 3 mu m.
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| 7. |
- Yang, Lily, et al.
(författare)
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Proximitized Josephson junctions in highly-doped InAs nanowires robust to optical illumination
- 2021
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:7
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the effects of optical-frequency light on proximitized InAs/Al Josephson junctions based on highly n-doped InAs nanowires at varying incident photon flux and at three different photon wavelengths. The experimentally obtained IV curves were modeled using a resistively shunted junction model which takes scattering at the contact interfaces into account. Despite the fact that the InAs weak link is photosensitive, the Josephson junctions were found to be surprisingly robust, interacting with the incident radiation only through heating, whereas above the critical current our devices showed non-thermal effects resulting from photon exposure. Our work indicates that Josephson junctions based on highly-doped InAs nanowires can be integrated in close proximity to photonic circuits. The results also suggest that such junctions can be used for optical-frequency photon detection through thermal processes by measuring a shift in critical current.
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| 8. |
- Zeuner, Katharina, et al.
(författare)
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On-Demand Generation of Entangled Photon Pairs in the Telecom C-Band with InAs Quantum Dots
- 2021
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Ingår i: ACS Photonics. - : AMER CHEMICAL SOC. - 2330-4022. ; 8:8, s. 2337-2344
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Tidskriftsartikel (refereegranskat)abstract
- Entangled photons are an integral part in quantum optics experiments and a key resource in quantum imaging, quantum communication, and photonic quantum information processing. Making this resource available on-demand has been an ongoing scientific challenge with enormous progress in recent years. Of particular interest is the potential to transmit quantum information over long distances, making photons the only reliable flying qubit. Entangled photons at the telecom C-band could be directly launched into single-mode optical fibers, enabling worldwide quantum communication via existing telecommunication infrastructure. However, the on-demand generation of entangled photons at this desired wavelength window has been elusive. Here, we show a photon pair generation efficiency of 69.9 +/- 3.6% in the telecom C-band by an InAs/GaAs semiconductor quantum dot on a metamorphic buffer layer. Using a robust phonon-assisted two-photon excitation scheme we measure a maximum concurrence of 91.4 +/- 3.8% and a peak fidelity to the Phi(+) state of 95.2 +/- 1.1%, verifying on-demand generation of strongly entangled photon pairs and marking an important milestone for interfacing quantum light sources with our classical fiber networks.
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