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Christine Silberhorn - One of the best experts on this subject based on the ideXlab platform.

  • high performance source of spectrally pure polarization Entangled Photon pairs based on hybrid integrated bulk optics
    Optics Express, 2018
    Co-Authors: Evan Meyerscott, Nidhin Prasannan, Christof Eigner, Viktor Quiring, John M Donohue, Sonja Barkhofen, Christine Silberhorn
    Abstract:

    Entangled Photon pair sources based on bulk optics are approaching optimal design and implementation, with high state fidelities, spectral purities and heralding efficiencies, but generally low brightness. Integrated entanglement sources, while providing higher brightness and low-power operation, often sacrifice performance in output state quality and coupling efficiency. Here we present a polarization-Entangled pair source based on a hybrid approach of waveguiding and bulk optics, addressing every metric simultaneously. We show 96 % fidelity to the singlet state, 82 % Hong-Ou-Mandel interference visibility, 43 % average Klyshko efficiency, and a high brightness of 2.9 × 106 pairs/(mode·s·mW), while requiring only microwatts of pump power.

  • high performance source of spectrally pure polarization Entangled Photon pairs based on hybrid integrated bulk optics
    arXiv: Quantum Physics, 2018
    Co-Authors: Evan Meyerscott, Nidhin Prasannan, Christof Eigner, Viktor Quiring, John M Donohue, Sonja Barkhofen, Christine Silberhorn
    Abstract:

    Entangled Photon pair sources based on bulk optics are approaching optimal design and implementation, with high state fidelities, spectral purities and heralding efficiencies, but generally low brightness. Integrated entanglement sources, while providing higher brightness and low-power operation, often sacrifice performance in output state quality and coupling efficiency. Here we present a polarization-Entangled pair source based on a hybrid approach of waveguiding and bulk optics, addressing every metric simultaneously. We show 96% fidelity to the singlet state, 82% Hong-Ou-Mandel interference visibility, 43% average Klyshko efficiency, and a high brightness of $2.9\times10^6$ pairs/(mode$\cdot$s$\cdot$mW), while requiring only microwatts of pump power.

  • a source of polarization Entangled Photon pairs interfacing quantum memories with telecom Photons
    New Journal of Physics, 2014
    Co-Authors: Christoph Clausen, Christine Silberhorn, W Sohler, Harald Herrmann, Felix Bussieres, Alexey Tiranov, Mikael Afzelius, Nicolas Gisin
    Abstract:

    We present a source of polarization-Entangled Photon pairs suitable for the implementation of long-distance quantum communication protocols using quantum memories. Photon pairs with wavelengths 883nm and 1338nm are produced by coherently pumping two periodically poled nonlinear waveguides embedded in the arms of a polarization interferometer. Subsequent spectral filtering reduces the bandwidth of the Photons to 240 MHz. The bandwidth is wellmatched to a quantum memory based on an Nd:YSO crystal, to which, in addition, the center frequency of the 883nm Photons is actively stabilized. A theoretical model that includes the effect of the filtering is presented and accurately fits the measured correlation functions of the generated Photons. The model can also be used as a way to properly assess the properties of the source. The quality of the entanglement is revealed by a visibility of =

  • post selection free integrated optical source of non degenerate polarization Entangled Photon pairs
    Optics Express, 2013
    Co-Authors: Harald Herrmann, Abu Thomas, W Sohler, Xu Yang, Andreas Poppe, Christine Silberhorn
    Abstract:

    We present an integrated source of polarization Entangled Photon pairs in the telecom regime, which is based on type II-phasematched parametric down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled lithium niobate. The domain grating – consisting of an interlaced bi-periodic structure – is engineered to provide simultaneous phase-matching of two PDC processes, and enables the direct generation of non-degenerate, polarization Entangled Photon pairs with a brightness of B = 7 × 103 pairs/(s×mW×GHz). The spatial separation of the Photon pairs is accomplished by a fiber-optical multiplexer facilitating a high compactness of the overall source. Visibilities exceeding 95 % and a violation of the Bell inequality with S = 2.57±0.06 could be demonstrated.

  • post selection free integrated optical source of non degenerate polarization Entangled Photon pairs
    arXiv: Quantum Physics, 2013
    Co-Authors: Harald Herrmann, Abu Thomas, W Sohler, Xu Yang, Andreas Poppe, Christine Silberhorn
    Abstract:

    We present an integrated source of polarization Entangled Photon pairs in the telecom regime, which is based on type II-phasematched parametric down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled lithium niobate. The domain grating -- consisting of an interlaced bi-periodic structure -- is engineered to provide simultaneous phase-matching of two PDC processes, and enables the direct generation of non-degenerate, polarization Entangled Photon pairs with a brightness of $B=7\times10^3$ pairs/(s mW GHz). The spatial separation of the Photon pairs is accomplished by a fiber-optical multiplexer facilitating a high compactness of the overall source. Visibilities exceeding 95% and a violation of the Bell inequality with $S=2.57\pm0.06$ could be demonstrated.

Alexander Ling - One of the best experts on this subject based on the ideXlab platform.

  • broadband pumped polarization Entangled Photon pair source in a linear beam displacement interferometer
    Applied Physics Letters, 2020
    Co-Authors: Alexander Lohrmann, Chithrabhanu Perumangatt, Aitor Villar, Alexander Ling
    Abstract:

    We experimentally demonstrate a source of polarization Entangled Photon-pairs based on a single periodically poled potassium titanyl phosphate crystal pumped with a broadband, free running laser diode. The crystal is placed within a linear beam-displacement interferometer and emits Photon-pairs based on type-0 spontaneous parametric downconversion. We observe pair rates of 0.56 Mpairs/s/mW in a single spatial mode with a polarization visibility of 97.7% over a spectral range of 100 nm. This experiment demonstrates a pathway toward observing gigacount rates of polarization Entangled Photon pairs by using high-power free-running laser diodes with fast multiplexed detectors.We experimentally demonstrate a source of polarization Entangled Photon-pairs based on a single periodically poled potassium titanyl phosphate crystal pumped with a broadband, free running laser diode. The crystal is placed within a linear beam-displacement interferometer and emits Photon-pairs based on type-0 spontaneous parametric downconversion. We observe pair rates of 0.56 Mpairs/s/mW in a single spatial mode with a polarization visibility of 97.7% over a spectral range of 100 nm. This experiment demonstrates a pathway toward observing gigacount rates of polarization Entangled Photon pairs by using high-power free-running laser diodes with fast multiplexed detectors.

  • broadband pumped polarization Entangled Photon pair source in a linear beam displacement interferometer
    arXiv: Quantum Physics, 2019
    Co-Authors: Alexander Lohrmann, Chithrabhanu Perumangatt, Aitor Villar, Alexander Ling
    Abstract:

    We experimentally demonstrate a source of polarization Entangled Photon-pairs based on a single periodically-poled potassium titanyl phosphate (PPKTP) crystal pumped with a broadband, free running laser diode.The crystal is placed within a linear beam-displacement interferometer, and emits Photon-pairs based ontype-0 spontaneous parametric downconversion (SPDC). We observe pair rates of 0.56 Mpairs/s/mW in a single spatial mode with a polarization visibility of 97.7% over a spectral range of 100 nm. This experiment demonstrates a pathway towards observing Gigacount rates of polarization Entangled Photon pairs by using high-power free-running laser diodes with fast multiplexed detectors.

  • high fidelity field stop collection for polarization Entangled Photon pair sources
    Applied Physics Letters, 2018
    Co-Authors: Alexander Lohrmann, Aitor Villar, Arian Stolk, Alexander Ling
    Abstract:

    We present an experimental demonstration of a bright and high fidelity polarization Entangled Photon pair source. The source is constructed using two critically phase matched β-Barium Borate crystals with parallel optical axes, and Photon pairs are collected after filtering with a circular field stop. Near-unity fidelities are obtained with detected pair rates exceeding 100 000 pairs/s mW, approaching the brightness of practical quasi-phase matched Entangled Photon sources. We find that the brightness scales linearly with the crystal length. We present models supporting the experimental data and propose strategies for further improvement. The source design is a promising candidate for emerging quantum applications outside of laboratory environments.

  • experimental Entangled Photon pair generation using crystals with parallel optical axes
    Optics Express, 2018
    Co-Authors: Aitor Villar, Alexander Lohrmann, Alexander Ling
    Abstract:

    We present an optical design where polarization-Entangled Photon pairs are generated within two β-Barium Borate crystals whose optical axes are parallel. This design increases the spatial mode overlap of the emitted Photon pairs enhancing single mode collection without the need for additional spatial walk-off compensators. The observed Photon pair rate is at least 65 000 pairs/s/mW with a quantum state fidelity of 99.53 ± 0.22% when pumped with an elliptical spatial profile.

  • high fidelity field stop collection for polarization Entangled Photon pair sources
    arXiv: Quantum Physics, 2018
    Co-Authors: Alexander Lohrmann, Aitor Villar, Arian Stolk, Alexander Ling
    Abstract:

    We present an experimental demonstration of a bright and high fidelity polarization Entangled Photon pair source. The source is constructed using two critically phase matched $\beta$-Barium Borate crystals with parallel optical axes and Photon pairs are collected after filtering with a circular field-stop. Near unity fidelities are obtained with detected pair rates exceeding \SI{100000}{pairs/\s/\mW} approaching the brightness of practical quasi-phase matched Entangled Photon sources. We find that the brightness scales linearly with the crystal length. We present models supporting the experimental data and propose strategies for further improvement. The source design is a promising candidate for emerging quantum applications outside of laboratory environments.

Klaus D Jons - One of the best experts on this subject based on the ideXlab platform.

  • bright nanoscale source of deterministic Entangled Photon pairs violating bell s inequality
    Scientific Reports, 2017
    Co-Authors: Klaus D Jons, Marijn A M Versteegh, Dan Dalacu, P J Poole, Angelo Gulinatti, Andrea Giudice, Lucas Schweickert, Val Zwiller
    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 ~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.

  • bright nanoscale source of deterministic Entangled Photon pairs violating bell s inequality
    arXiv: Mesoscale and Nanoscale Physics, 2015
    Co-Authors: Klaus D Jons, Marijn A M Versteegh, Dan Dalacu, P J Poole, Angelo Gulinatti, Andrea Giudice, Lucas Schweickert, Val Zwiller
    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 $\sim$200 kHz Entangled Photon-pairs at the first lens under 80\,MHz pulsed excitation, which is a 20 times enhancement as compared to a bare quantum dot without a Photonic nanostructure. The performed Bell test using the Clauser-Horne-Shimony-Holt inequality reveals a clear violation ($S_{\text{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\,\pm\,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.

  • observation of strongly Entangled Photon pairs from a nanowire quantum dot
    Nature Communications, 2014
    Co-Authors: Marijn A M Versteegh, Klaus D Jons, Michael E Reimer, Dan Dalacu, P J Poole, Angelo Gulinatti, Andrea Giudice, Val Zwiller
    Abstract:

    A bright Photon source that combines high-fidelity entanglement, on-demand generation, high extraction efficiency, directional and coherent emission, as well as position control at the nanoscale is required for implementing ambitious schemes in quantum information processing, such as that of a quantum repeater. Still, all of these properties have not yet been achieved in a single device. Semiconductor quantum dots embedded in nanowire waveguides potentially satisfy all of these requirements; however, although theoretically predicted, entanglement has not yet been demonstrated for a nanowire quantum dot. Here, we demonstrate a bright and coherent source of strongly Entangled Photon pairs from a position-controlled nanowire quantum dot with a fidelity as high as 0.859±0.006 and concurrence of 0.80±0.02. The two-Photon quantum state is modified via the nanowire shape. Our new nanoscale Entangled Photon source can be integrated at desired positions in a quantum Photonic circuit, single-electron devices and light-emitting diodes.

  • on demand generation of indistinguishable polarization Entangled Photon pairs
    Nature Photonics, 2014
    Co-Authors: Markus Muller, Samir Bounouar, Klaus D Jons, Martin Glassl, P Michler
    Abstract:

    Polarization-Entangled Photon pairs are generated from an In(Ga)As quantum dot by setting the pump intensity such that the inversion of the quantum dot from the ground to the biexcitonic state is the most probable transition. On-demand generation is demonstrated with an ultrahigh purity, a high entanglement fidelity and high two-Photon-interference non-post-selective visibilities.

Jianwei Pan - One of the best experts on this subject based on the ideXlab platform.

  • bell test over extremely high loss channels towards distributing Entangled Photon pairs between earth and the moon
    Physical Review Letters, 2018
    Co-Authors: Yuan Cao, Juan Yin, Cheng-zhi Peng, Yuao Chen, Wenjie Zou, Qi Shen, Shengkai Liao, Jigang Ren, Jianwei Pan
    Abstract:

    Quantum entanglement was termed ``spooky action at a distance'' in the well-known paper by Einstein, Podolsky, and Rosen. Entanglement is expected to be distributed over longer and longer distances in both practical applications and fundamental research into the principles of nature. Here, we present a proposal for distributing Entangled Photon pairs between Earth and the Moon using a Lagrangian point at a distance of 1.28 light seconds. One of the most fascinating features in this long-distance distribution of entanglement is as follows. One can perform the Bell test with human supplying the random measurement settings and recording the results while still maintaining spacelike intervals. To realize a proof-of-principle experiment, we develop an Entangled Photon source with 1 GHz generation rate, about 2 orders of magnitude higher than previous results. Violation of Bell's inequality was observed under a total simulated loss of 103 dB with measurement settings chosen by two experimenters. This demonstrates the feasibility of such long-distance Bell test over extremely high-loss channels, paving the way for one of the ultimate tests of the foundations of quantum mechanics.

  • generation of narrow band polarization Entangled Photon pairs for atomic quantum memories
    Physical Review Letters, 2008
    Co-Authors: Xiao-hui Bao, Jian Yang, Yong Qian, Han Zhang, Zengbing Chen, Tao Yang, Jianwei Pan
    Abstract:

    We report an experimental realization of a narrow band polarization-Entangled Photon source with a linewidth of 9.6 MHz through cavity-enhanced spontaneous parametric down-conversion. This linewidth is comparable to the typical linewidth of atomic ensemble-based quantum memories. Single-mode output is realized by setting a reasonable cavity length difference between different polarizations, using of temperature controlled etalons and actively stabilizing the cavity. The Entangled property is characterized with quantum state tomography, giving a fidelity of 94% between our state and a maximally Entangled state. The coherence length is directly measured to be 32 m through two-Photon interference.

Zhongfa Liao - One of the best experts on this subject based on the ideXlab platform.

  • long distance measurement device independent quantum key distribution with Entangled Photon sources
    Applied Physics Letters, 2013
    Co-Authors: Zhongfa Liao
    Abstract:

    We present a feasible method that can make quantum key distribution (QKD), both ultra-long-distance and immune, to all attacks in the detection system. This method is called measurement-device-independent QKD (MDI-QKD) with Entangled Photon sources in the middle. By proposing a model and simulating a QKD experiment, we find that MDI-QKD with one Entangled Photon source can tolerate 77 dB loss (367 km standard fiber) in the asymptotic limit and 60 dB loss (286 km standard fiber) in the finite-key case with state-of-the-art detectors. Our general model can also be applied to other non-QKD experiments involving entanglement and Bell state measurements.

  • long distance measurement device independent quantum key distribution with Entangled Photon sources
    arXiv: Quantum Physics, 2013
    Co-Authors: Zhongfa Liao
    Abstract:

    We present a practical method that can make quantum key distribution (QKD), for the first time, both ultra-long-distance and immune to all attacks in the detection system. This method is an important extension of the measurement-device-independent QKD (MDI-QKD) - MDI-QKD with Entangled Photon sources in the middle. By proposing a general model and simulating an entanglement based QKD experiment, we find that MDI-QKD with one Entangled Photon source in the middle can practically tolerate 77 dB combined loss (367km standard telecom fiber) in the asymptotic limit, and it can still tolerate 60 dB combined loss (286km standard telecom fiber) in the finite-key case with state-of-the-art detectors. Our general model can also be applied to other non-QKD experiments involving Entangled Photon sources and Bell state measurements.