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Cited by 908Semiconductor Quantum Structures and DevicesStrong Light-Matter InteractionsQuantum optics and atomic interactions

On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

Open access
Ding, Xing, He, Yu, Duan, Z.-C., Gregersen, Niels, Chen, M.-C., Unsleber, S., Maier, S., Schneider, Christian +4 more·2016·Physical Review Letters
DOI 10.1103/physrevlett.116.020401
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Abstract

Scalable photonic quantum technologies require on-demand single-photon sources with simultaneously high levels of purity, indistinguishability, and efficiency. These key features, however, have only been demonstrated separately in previous experiments. Here, by s-shell pulsed resonant excitation of a Purcell-enhanced quantum dot-micropillar system, we deterministically generate resonance fluorescence single photons which, at π pulse excitation, have an extraction efficiency of 66%, single-photon purity of 99.1%, and photon indistinguishability of 98.5%. Such a single-photon source for the first time combines the features of high efficiency and near-perfect levels of purity and indistinguishabilty, and thus opens the way to multiphoton experiments with semiconductor quantum dots.

AI snapshot

Written from the paper’s full text.

TL;DR

By pulsed s-shell resonant excitation of a Purcell-enhanced InAs/GaAs quantum dot in a micropillar, the authors generate on-demand resonance-fluorescence single photons at π pulse with 66% extraction efficiency, 99.1% purity, and 98.5% indistinguishability. They argue this combines high efficiency with near-perfect purity and indistinguishability, opening a path to scalable multiphoton experiments with semiconductor quantum dots.

Key findings

  • At π pulse excitation (24 nW, 81 MHz repetition rate), the source gives a count rate of 3.7 × 10⁶/s on a silicon single-photon detector, an overall system efficiency of 4.6%, and an estimated extraction efficiency of ∼66% into the first objective lens (NA = 0.68).
  • Single-photon purity is reported as g²(0) = 0.009(1) [abstract also states 0.009(2)], corresponding to 99.1% purity; the signal-to-background ratio is 40:1.
  • Two-photon Hong-Ou-Mandel interference gives raw/corrected visibilities of 96.4(3)% / 98.5(4)% at a 2.1 ns delay and 95.9(3)% / 97.8(4)% at a 12.4 ns delay; the abstract reports 98.5% indistinguishability.
  • The micropillar cavity has a measured Purcell factor of 6.3(4), with the shortest RF lifetime 83.9 ps at 7.8 K; the homogeneous linewidth is 1.91(7) GHz, close to the lifetime-limited 1.89 GHz.

Methods

  • A single self-assembled InAs/GaAs quantum dot embedded in a 2.5 μm diameter micropillar with 25.5 lower and 15 upper λ/4 AlAs/GaAs distributed Bragg reflectors, cooled in a cryogen-free bath cryostat tunable from 4.2 to 30 K.
  • Pulsed s-shell resonant excitation used a Ti:sapphire laser producing ∼3 ps pulses at 897.44 nm, filtered by a 45 GHz etalon, with cross-polarization confocal suppression of laser background exceeding 10⁷.
  • Characterization included microphotoluminescence, time-resolved resonance fluorescence, Hanbury Brown–Twiss measurement for g²(0), and Hong-Ou-Mandel interference at 2.1 ns and 12.4 ns delays, with corrections for detection and optical-path efficiencies.

Limitations

  • Stated: the overall system efficiency remains 4.6% and extraction efficiency 66%; the authors say these can be improved using orthogonal excitation/detection, near-unity-efficiency superconducting nanowire single-photon detection, antireflection coatings, and optimized microcavity fabrication for higher Purcell factor.
  • Stated: the inhomogeneous Gaussian linewidth of 1.14(9) GHz is attributed to spectral diffusion from charge fluctuations near the QD, and the extraction-efficiency estimate assumes perfect internal quantum efficiency of the QD.
  • Evident: the demonstration is a single cryogenic QD-micropillar device; scaling to multiphoton experiments would require time-bin encoding, demultiplexing, or similar approaches not demonstrated here, and the corrected indistinguishability values depend on correction for residual multiphoton probability.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1103/physrevlett.116.020401

Cites

61 of 61 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 32 cited sources checked · 0 supported · 0 flagged

  • Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    At π pulse excitation, the generated single photons have a photon indistinguishability of 98.5%.

    “have an extraction efficiency of 66%, single-photon purity of 99.1%, and photon indistinguishability of 98.5%.”
    • Also stated in: § 020401-3 · plain
      “we obtained the corrected degrees of indistinguishability to be 0.985 (4).”
    Quote in the paperSubstantial claim
  • Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    Pulsed s-shell resonant excitation of a Purcell-enhanced quantum dot-micropillar system deterministically generates resonance fluorescence single photons.

    “Here, by s-shell pulsed resonant excitation of a Purcellenhanced quantum dot-micropillar system, we deterministically generate resonance fluorescence single photons”
    Quote in the paperSubstantial claim
  • Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    At π pulse excitation, the generated single photons have an extraction efficiency of 66%.

    “have an extraction efficiency of 66%, single-photon purity of 99.1%, and photon indistinguishability of 98.5%.”
    • Also stated in: § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar · hedged
      “we estimate that 66% of the generated single photons are collected into the first objective lens (NA ¼ 0.68).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The internal quantum efficiency of the QD is perfect.
  • Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    At π pulse excitation, the generated single photons have a single-photon purity of 99.1%.

    “have an extraction efficiency of 66%, single-photon purity of 99.1%, and photon indistinguishability of 98.5%.”
    • Also stated in: § 020401-3 · plain
      “singlephoton purity of 99.1%”
    Quote in the paperSubstantial claim
  • Findingreasoning
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    After correcting for calibrated losses and assuming perfect internal quantum efficiency, 66% of generated single photons are collected into the first objective lens (NA=0.68).

    “and assuming perfect internal quantum efficiency of the QD, we estimate that 66% of the generated single photons are collected into the first objective lens (NA ¼ 0.68).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The internal quantum efficiency of the QD is perfect.
  • May combine two claims. 10
  • Classified as probably not a substantial claim. 7

  • May combine two claims.

    Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    At π pulse, the count rate is 3700000/sec under 81 MHz repetition rate, giving an overall system efficiency of 4.6%.

    “At the π pulse, we observe a count rate of 3700000= sec on a silicon single-photon detector, under 81 MHz repetition rate laser excitation, which gives an overall system efficiency of 4.6%.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    The photoluminescence intensity reaches a plateau at a temperature range of 4.5-10 K.

    “The photoluminescence intensity reaches a plateau at a temperature range of 4.5-10 K.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    In nonresonant excitation experiments, single-photon generation efficiencies typically increased asymptotically with pump power, and a trade-off between efficiency and single-photon purity and/or indistinguishability was observed.

    “In the nonresonant excitation experiments, single-photon generation efficiencies typically increased asymptotically with pump power, and a trade-off between efficiency and single-photon purity and/or indistinguishability were observed [5][6][7][8][9][10].”
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    Premisenone given
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    Most previous experiments either relied on nonresonant excitation of a QD microcavity that degraded photon purity and indistinguishability, or used resonant excitation of a QD in a planar cavity that limited extraction efficiency.

    “The reason is that most previous experiments either relied on nonresonant excitation of a QD microcavity that degraded the photon purity and indistinguishability, or used resonant excitation of a QD in a planar cavity that limited the extraction efficiency.”
    Quote in the paperSubstantial claim0 of 3 sources checked
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    Interpretationown data

    Increasing the time delay by 10 ns has a negligible effect on the photons' indistinguishability, in strong contrast to Ref. [9] that used nonresonant excitation.

    “In strong contrast to Ref. [9] that used nonresonant excitation, increasing the time delay by 10 ns has a negligible effect on the photons' indistinguishability”
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    Premisenone given
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    Pulsed s-shell resonant excitation has been demonstrated to yield near-unity indistinguishability by eliminating emission time jitter and dephasings, but only for QDs in planar cavities.

    “Pulsed s-shell resonant excitation has been demonstrated to yield a near-unity indistinguishability by eliminating emission time jitter and dephasings, however, only for QDs in planar cavities.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    The inhomogeneous component in the spectrum can be caused by spectral diffusion due to charge fluctuations in the vicinity of the QD.

    “The inhomogeneous (Gaussian) component in the spectrum can be caused by spectral diffusion due to charge fluctuations in the vicinity of the QD [20].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
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  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    By s-shell resonant laser excitation on a single QD with picosecond laser pulses, near-background-free resonance fluorescence has been obtained and allowed observation of Rabi oscillations.

    “By s-shell resonant laser excitation on a single QD with picosecond laser pulses, near-background-free resonance fluorescence (RF) has been obtained and allowed the observation of Rabi oscillations [11].”
    Quote in the paperSubstantial claim0 of 1 sources checked
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  • May combine two claims.

    Premisecitation
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    Under π pulse excitation, single photons have been deterministically generated with a single-photon purity of 98.8(2)% and indistinguishability of 97(2)%.

    “Under π pulse excitation, single photons have been deterministically generated with a single-photon purity of 98.8(2)% and indistinguishability of 97(2)%.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] source

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  • Classified as probably not a substantial claim.

    Premisecitation
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    A high degree of indistinguishability is at the heart of optical quantum computing, Boson sampling, and solid-state quantum networks.

    “Another crucial demand is that the photons should possess a high degree of indistinguishability, which is at the heart of optical quantum computing [2], Boson sampling [23], and solid-state quantum networks [24].”
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    Premisecitation

    Heralded single photons produced by parametric down conversion have served as the workhorse for multiphoton interferometric experiments in the past decades.

    “We compare the performance of the single-photon source created in this work with heralded single photons produced by parametric down conversion [27], which have served as the workhorse for multiphoton interferometric experiments in the past decades [2].”
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    Interpretationown data
    § On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

    The single-photon counts growing asymptotically with excitation laser power in previous nonresonant excitation experiments contrasts with the present observation, so near-unity efficiency would need very high power pumping in those previous experiments.

    “We note that this is in stark contrast to previous experiments with nonresonant excitation where the generated single-photon counts typically grow asymptotically with excitation laser power; thus, a near unity efficiency would need very high power pumping.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    High-efficiency extraction of transition-selective RF would allow fast (nsec), high-fidelity single-shot readout of single electron spins.

    “In addition to the photonic applications, the high-efficiency extraction of transitionselective RF would also allow a fast (nsec), high-fidelity single-shot readout of single electron spins [29].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
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    • The authors state this as an assumption: The internal quantum efficiency of the QD is perfect.

  • May combine two claims.

    Interpretationown data

    For applications such as Boson sampling that need single photons as input, the single-photon source realized here is superior, as it is ten times brighter, near perfectly pure and indistinguishable, and requires a pump power that is 7 orders of magnitude lower.

    “For applications such as Boson sampling [23] that needs single photons as input, the single-photon source realized here is superior, as it is ten times brighter, near perfectly pure and indistinguishable, and requires a pump power that is 7 orders of magnitude lower.”
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    Premisecitation

    In the previous demonstration of eight-photon entanglement, sources of triggered single photons were generated with a count rate of 310000/sec, multiphoton emission probability of 2.9%, raw indistinguishability of 76%, under laser pump power of 880 mW.

    “In the previous demonstration of the largest, eight-photon entanglement [28], sources of triggered single photons were generated with a count rate of 310000= sec, multiphoton emission probability of 2.9% and raw indistinguishablility of 76%, under a laser pump power of 880 mW.”
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    Interpretationreasoning

    Immediate applications include implementation of Boson sampling with time-bin encoding using a loop-based architecture.

    “Immediate applications include implementation of Boson sampling [23] with time-bin encoding using a loop-based architecture [26].”
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16 of 16

  • The authors state this as an assumption.

    The internal quantum efficiency of the QD is perfect.

    “assuming perfect internal quantum efficiency of the QD”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • With the rapid development of other types of single-photon sources, such as those based on quantum dots, it is likely this obstacle will soon be overcome.

    “Moreover, with the rapid development of other types of singlephoton sources, such as those based on quantum dots, 45,46 it is likely this obstacle will soon be overcome.”

    From Integrated-optics heralded controlled-NOT gate for polarization-encoded qubits (2018) · cites this paper as [45]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Summary gives a different photon indistinguishability

    Minor

    The summary reports 98.6% indistinguishability, whereas the opening paragraph reports 98.5% for the π-pulse source, matching the results section's corrected value of 0.985(4).

  • Different uncertainties reported for the same antibunching measurement

    Minor

    The π-pulse second-order correlation is reported as 0.009(2) in the overview but as 0.009(1) in the results and Fig. 2 caption. The central value agrees, but its reported uncertainty does not.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. S. Aaronson, 2011, Proceedings of the 43rd Annual ACM Symposium on Theory of Computing, 2011, San Jose

Cited by

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Related

Authors
Ding, X., He, Y., Duan, Z.-C., Gregersen, N., Chen, M.-C., Unsleber, S., Maier, S., Schneider, C., Kamp, M., Höfling, S., Lu, C.-Y., & Pan, J.-W.
Affiliations
  • University of Science and Technology of China (CN)
  • Technical University of Denmark (DK)
  • University of Würzburg (DE)
ORCID
Venue
Physical Review Letters
Publisher
American Physical Society (APS)
Published
2016-01-14
Volume
116
Issue
2
Pages
020401-020401
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
DOI
10.1103/physrevlett.116.020401
OpenAlex
W2223884576
Semantic Scholar
c89cbecf3d2c4fdfcb92c521bd92a9060d72f4ae
Cited by
908
References
61
Citations by year
2026: 55 · 2025: 62 · 2024: 64 · 2023: 69 · 2022: 80 · 2021: 88 · 2020: 88 · 2019: 115 · 2018: 112 · 2017: 121 · 2016: 53
FWCI
63.21
Type
journal article
Language
en
Open access
Licence
link.aps.org/licenses/aps-default-license (vor)
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • Technical University of Denmark, DTU Orbit (Technical University of Denmark, DTU) (submittedVersion, other-oa)
  • St Andrews Research Repository (St Andrews Research Repository) (submittedVersion)
  • arXiv (Cornell University)
Funders
  • National Natural Science Foundation of China
  • Chinese Academy of Sciences
  • Danish Research Council for Technology and Production
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Semiconductor Quantum Structures and Devices
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Strong Light-Matter Interactions
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum optics and atomic interactions
Keywords
single-photon sources, quantum dots, micropillars, Purcell effect, resonance fluorescence, photon indistinguishability, photon extraction efficiency, semiconductor quantum dots

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