Abstract
Developing a quantum photonics network requires a source of veryhighfidelity single photons. An outstanding challenge is to produce a transformlimited singlephoton emitter to guarantee that single photons emitted far apart in the time domain are truly indistinguishable. This is particularly difficult in the solidstate as the complex environment is the source of noise over a wide bandwidth. A quantum dot is a robust, fast, bright and narrowlinewidth emitter of single photons; layerbylayer growth and subsequent nanofabrication allow the electronic and photonic states to be engineered. This represents a set of features not shared by any other emitter but transformlimited linewidths have been elusive. Here, we report transformlimited linewidths measured on second timescales, primarily on the neutral exciton but also on the charged exciton close to saturation. The key feature is control of the nuclear spins, which dominate the exciton dephasing via the Overhauser field.
Introduction
A key goal in quantum communication is to create highly indistinguishable photons that are separated in space by more than 100 km for deviceindependent quantum key distribution and for a quantum repeater^{1}. This is potentially possible using a solidstate source, a semiconductor quantum dot. A single quantum dot mimics a twolevel atom and single photons are generated either by spontaneous emission from the upper level^{2,3,4} or by coherent scattering of a resonant laser^{5,6,7}. The radiative lifetime is typically τ_{r}=800 ps (ref. 8). There is evidence that on this timescale and at low temperature, there is negligible pure upper level decoherence^{5,6,7,9}. Photons emitted subsequently are close to indistinguishable^{3,10}. (At higher temperatures^{9,11,12,13}, equivalently at low temperature but at high Rabi couplings^{14,15}, phonons dephase the upper level.) A key remaining issue concerns the wandering of the centre frequency over times much longer than τ_{r} (refs 16, 17, 18). This wandering is highly problematic in any quantum photonics network: the quantum dot detunes from the common optical frequency and becomes dark; equivalently, the indistinguishability of quantum dot single photons generated far apart in the time domain is reduced. Active singlequantumdot stabilization is possible but is presently limited to correcting for very slow drifts and in any case comes at the expense of complexity^{18,19}. Eliminating the spectral wanderings would be highly advantageous.
The spectral wanderings can be conveniently probed simply by measuring the optical linewidth. Measured on millisecond or even second timescales, the quantum dot optical linewidth Γ is larger than the transform limit Γ_{0}=ℏ/τ_{r} (refs 16, 17, 20, 21). In fact singlequantumdot linewidths have remained stubbornly 50–100% above the transform limit even under the most favourable conditions (highquality material, low temperature, charge control via Coulomb blockade and resonant excitation). We report here two regimes in which we observe transformlimited quantum dot optical linewidths even when measured on second timescales. One regime applies to the neutral exciton, X^{0}, the other to the charged exception, X^{1−}.
The X^{0} transition is split into two linearly polarized transitions by the electron–hole exchange, the socalled fine structure, corresponding to an admixture of the spin ±1 states (Fig. 1a). The splitting between the two transitions increases in an applied magnetic field, quadratically initially (Fig. 1c). The magnetic field is applied externally or it arises from a net polarization in the nuclear spins, which acts on the electron spin via the Overhauser field, B_{N}. The X^{1−} exhibits a single line at zero magnetic field (Fig. 1b) splitting linearly in magnetic field, again via an external field or Overhauser field (Fig. 1d). Both excitons exhibit large and similar d.c. Stark shifts (dependence of energy on electric field F), ∼25 μeV cm kV^{−1} (ref. 22). Charge noise leads to an inhomogeneous broadening of both X^{0} and X^{1−} transitions via the d.c. Stark shift. This determines the inhomogeneous broadening for quantum dots in poorquality material or quantum dots in highquality material but with nonresonant excitation. In addition, both excitons are sensitive to spin noise, that is, fluctuations in the Overhauser field, but with different sensitivities. For X^{0}, the sensitivity is second order as the hole ‘shields’ the electron from the spin noise; for X^{1−} the sensitivity is first order on account of the unpaired electron in the X^{1−} ground state. For instance, a typical Overhauser field of 20 mT (ref. 23) (arising from incomplete cancellation of the ∼10^{5} nuclear spins^{24,25}) leads to a linewidth contribution in the case of X^{1−} of ∼0.5–1.0 μeV. Experimentally, there is strong evidence that in this cold, clean limit, spin noise and not charge noise is responsible for the X^{1−} inhomogeneous broadening^{18,21}. Despite the different sensitivity to spin noise the X^{0} and X^{1−} linewidths are very similar^{16,17,21}.
The approach here is to suppress the effects of charge noise by working in the ideal limit (highquality material at low temperature, resonant excitation on a quantum dot in the Coulomb blockade regime), to compare X^{0} and X^{1−} on the same quantum dot and to suppress the effects of spin noise by a search of the available parameter space. The improvement in the optical linewidth arises as a consequence of improved optical control of the nuclear spins associated with the quantum dot. It is noteworthy that the hyperfine interaction^{26,27} limits also the entanglement in the biexciton cascade^{28,29}.
Results
X^{0} singlequantumdot optical linewidth
A typical X^{0} resonance fluorescence (RF) spectrum is shown in Fig. 2a with Ω/Γ_{0}=0.5 where Ω is the Rabi coupling. The linewidth is a factor of 1.4 larger than the transform limit (for this particular quantum dot, ). The transform limit Γ_{0} is measured by scanning the optical resonance very quickly such that the fluctuations are frozen during the measurement^{21} (Fig. 2c). The result is corroborated by measuring the radiative lifetime, either by recording a decay curve following pulsed excitation or by recording an intensity correlation g^{(2)}: the results agree to within the random errors of ∼5% (Supplementary Note 1 and Supplementary Fig. 1).
Figure 3a shows Γ versus V_{g} on the neutral exciton, X^{0}, measured below but close to saturation, Ω/Γ_{0}=0.5. At the edges of the Coulomb blockade plateau, Γ rises rapidly on account of fast electron spin dephasing via cotunnelling with the Fermi sea^{30}. This process slows down as V_{g} moves away from the plateau edges. The new feature is that a ‘sweet spot’ exists close to the negative V_{g} end of the plateau with minimum linewidth 1.19±0.13 μeV (Fig. 3a,b). Accounting for the small power broadening, the ideal limit is . Within the measurement uncertainties of 10%, the transform limit is therefore achieved. As V_{g} raised to the positive side of the sweet spot, Γ increases beyond the ideal limit (Fig. 3a).
It is instructive to investigate the sources of noise. A diagnostic is a noise spectrum N_{QD}(f), a Fourier transform of the RF timetrace (Supplementary Note 2 and Supplementary Fig. 2). From the known relationships between RF signal, detuning δ, Rabi coupling Ω, electric field F and the Overhauser field B_{N}, the variances F_{r.m.s.} and B_{N,r.m.s.} can be determined from the noise spectrum^{21} (Supplementary Note 3). The increase in linewidth above the transform limit represents a sum over all noise sources from the scanning frequency, about 1 Hz, to Γ_{0}/ℏ, about 1 GHz. The noise spectra at the lowbias end (the sweet spot), the centre of the plateau and the positivebias end are shown in Fig. 3c. There is a Lorentzian feature with linewidth 30 Hz (noise correlation time 30 ms) and a second Lorentzian feature at higher frequencies with linewidth 200 kHz (correlation time 5 μs). The origin of the two features in the noise spectrum can be identified by exploiting the different X^{0} response to charge noise and spin noise: charge noise moves both X^{0} peaks rigidly together; spin noise moves them apart or closer together, a ‘breathing’ motion. A twolaser experiment enables us to distinguish between these two possibilities. Specifically, we record X^{0} noise spectra with two lasers with frequencies separated in frequency by the fine structure. On detuning both lasers from δ=0 to δ=Γ/2, the sensitivity to charge noise increases (changing from second order to first order) yet the sensitivity to spin noise decreases (remaining second order but with a reduced prefactor) (Supplementary Note 4 and Supplementary Fig. 3). In the experiment, switching from 〈δ〉=0 to 〈δ〉=Γ/2 causes the noise power of the lowfrequency component to increase markedly (Fig. 3d) identifying it as charge noise. However, the frequency sum over the charge noise gives a contribution to Γ smaller than 0.05 μeV (Supplementary Note 5), a negligible value. (We note that both the d.c. Stark coefficient and Γ vary from quantum dot to quantum dot yet there is no correlation between the two (Supplementary Note 6 and Supplementary Fig. 4), pointing also to the unimportance of charge noise in the optical linewidth.) Conversely, the noise power of the highfrequency component decreases on detuning both lasers from δ=0 to δ=Γ/2, identifying it as spin noise (Fig. 3d). Furthermore, noise spectra measured at 〈δ〉=0 but with a single laser tuned to one of the X^{0} transitions show that the lowfrequency noise, the charge noise, is similar for all three biases yet the highfrequency noise, the spin noise, increases with increasing bias (Fig. 3c). This confirms that the highfrequency noise, the spin noise, is responsible for the inhomogeneous linewidth: the integrated spin noise is vanishingly small at the sweet spot, increasing at the centre of the plateau, and increasing further at the positivebias edge.
In general, the X^{0} Γ versus Ω curve does not follow exactly the textbook result for a twolevel system (Supplementary Note 7 and Supplementary Fig. 5). The Ω dependence of N_{QD}(f) is highly revealing (Fig. 4a, Supplementary Note 8 and Supplementary Fig. 6). In the centre of the plateau, as Ω increases the X^{0} spin noise also increases (Fig. 4a). increases roughly linearly with Ω reaching at the highest couplings extremely high values, 300 mT (Fig. 4c). ( is determined by a Monte Carlo simulation of N_{QD}(f) including an ensemble of fluctuating nuclei—this is robust as X^{0} is sensitive only to the vertical component of B_{N} (Supplementary Note 3).) The large would appear to prohibit transformlimited linewidths on X^{0} at all but the very lowest optical couplings. However, at the sweet spot, this mechanism is clearly suppressed: reduces to <50 mT and approaches the value for a quantum dot in the ground state.
The existence of the X^{0} sweet spot is a robust phenomenon. It exists on all the quantum dots investigated in this particular sample, on quantum dots from other samples from the same wafer and from samples from other wafers of a similar but nonidentical design (Supplementary Note 9 and Supplementary Fig. 7). A very striking example is the observation of the sweet spot on a ptype fieldeffect device (Supplementary Fig. 7(e)). Choosing the correct bias allows us to achieve X^{0} transformlimited lifetimes (to within the random error of 0.1 μeV) in each case.
X^{1−} singlequantumdot optical linewidth
A typical X^{1−} resonance fluorescence spectrum is shown in Fig. 2b with Ω/Γ_{0}=0.4 (same quantum dot as in Fig. 2a). The linewidth is a factor of 2.0 larger than the transform limit (for this particular quantum dot, ). For X^{1−}, it is clear that the nuclear spins are a significant source of inhomogeneous broadening. As a function of bias, the X^{1−} linewidth is smallest in the centre of the Coulomb blockade plateau, rising at the edges. This is consistent with a cotunnelling dominated mechanism^{30} (Supplementary Note 9 and Supplementary Fig. 7(a)). We investigate the spin noise and in particular its Ω dependence via the noise spectra. Figure 4b shows that the X^{1−} spin noise decreases as Ω increases, corresponding to a decrease in (Fig. 4d). (The distinction between charge noise and spin noise can be made in the case of X^{1−} simply by changing the detuning from 〈δ〉=0 to 〈δ〉=Γ/2 in a onelaser experiment^{21}. X^{1−} responds to all three components of B_{N}, a more complex problem than that for X^{0}, and instead is determined (Fig. 4d) with lower systematic error from the twolaser experiment described below.)
We address whether the spin noise reduction in the case of X^{1−} is sufficient to achieve transformlimited optical linewidths. The Ω dependence of can be described extremely well with the twolevel result including an inhomogeneous broadening γ (Fig. 5b, Supplementary Note 7 and Supplementary Fig. 5). At low Ω, Γ is determined by Γ_{0} and γ; at higher Ω, Γ increases (power broadening) and γ becomes irrelevant. We can therefore determine the ideal limit (Γ versus Ω with γ=0) and below saturation, the inhomogeneous broadening is clearly significant (Fig. 5b). However, this relatively simple linewidth measurement is complex to interpret as the spin noise is a function of both Rabi energy and detuning. To simplify matters, we performed the experiment with two lasers. The concept is that the stronger, constant frequency pump laser (Ω_{2}, δ_{2}) determines the spin noise, and the weaker probe laser (Ω_{1}, δ_{1}) measures the optical linewidth. Figure 5a shows measured by sweeping δ_{1} versus δ_{2} for Ω_{1}=0.23, Ω_{2}=0.80 μeV. For large δ_{2}, the pump laser has no effect on Γ; power broadening is irrelevant and Γ is far from the transform limit. For small δ_{2} however, Γ decreases, despite the power broadening induced by Ω_{2}. Taking into account power broadening, Γ reduces to the ideal limit. Figure 5b shows the results as Ω_{2} increases: for Ω/Γ_{0} >0.75, transformlimited optical linewidths are achieved (to within the random error of 10%). The spin noise reduction on driving X^{1−} with the pump laser is accompanied by a profound change in the probe spectrum: the optical resonance now splits into two resonances (Fig. 5c). The splitting reflects a static electron Zeeman splitting in the singleelectron ground state, B_{N}=58 mT in Fig. 5c, with B_{N} increasing with Ω_{2} (Fig. 5d, Supplementary Note 10 and Supplementary Fig. 8). Equivalently, even without an applied magnetic field^{31}, a nuclear spin polarization is created by the optical coupling. This demonstrates that the laser locks the nuclear spins into an eigenstate of the ΣI_{z} operator. (We comment that significant nuclear spin polarizations can be achieved in an applied magnetic field^{26,27}, for instance via ‘dragging’ with resonant excitation^{32}, but we find that the optical linewidths increase in this regime.)
Discussion
The experiments reveal a remarkable dependence of the spin noise on charge. In the centre of the plateaus, resonant excitation of X^{0} enhances spin noise yet resonant optical excitation of X^{1−} suppresses spin noise. Concomitant with the different B_{N,r.m.s.} values are the associated B_{N}correlation times, much shorter for X^{0} (5 μs) than for X^{1−} (100 μs)^{21,33}. We note that the scanning frequency dependence (Fig. 2c) reveals a 100μs noise correlation time for both X^{0} and X^{1−}: at higher enough scanning frequencies, X^{0} is driven too briefly for any nuclear noise enhancement to be active. This points to the fact that the reduced correlation time and increased amplitude of the spin noise as measured on X^{0} is related to the constant optical driving. Fortunately, at a particular bias, the nuclear spin ‘shakeup’ on driving X^{0} can be turned off and transformlimited linewidths can be achieved: the charge noise is too small to matter and the electron–hole exchange shields the exciton from the remaining nuclear spin noise.
Once the charge noise has been suppressed by using clean devices and the nuclear spin effects have been bypassed, the fidelity of the photons is limited by the phonons. The zero phonon line (ZPL) accounts for 95% of the emission^{12,19}, a very high ratio for a solidstate emitter. The 5% nonZPL photons can be filtered out without too much trouble but at the cost of a slight increase in shot noise. The phononrelated broadening of the ZPL is however very small at low temperature^{9,12}. Once the device engineering described here has been combined with photonic mode engineering to boost the extraction efficiency^{34}, there are excellent prospects for creating a fast and efficient source of indistinguishable photons using a semiconductor.
The mechanisms by which the nuclear spin noise respond to resonant optical excitation are unknown. For X^{1−}, the data are compatible with a ‘narrowing’ of the nuclear spin distribution, perhaps caused by continuous weak measurement via the narrowband laser^{35}. The correlation time is compatible with the nuclear spin dipole–dipole interaction. For X^{0} it is unlikely that the standard electron spin–nuclear spin contact hyperfine interaction can offer an explanation; it is also unlikely that the bare dipole–dipole interaction can account for the short correlation time. One possibility is that the hole in the X^{0} is important. First, a hole has a complex hyperfine interaction, containing a term (I_{+}J_{z}+I−J_{z}), exactly the structure required to shakeup the nuclear spins on creation of a hole (I is the nuclear spin and J the hole pseudospin)^{36}. While the coefficient of this term is likely to be small, it can have significant consequences should the dark X^{0} state be occupied for times far exceeding the radiative lifetime^{36}. A second possibility is that the hyperfine interaction renders the X^{0} sensitive to the nuclear spins by altering the phase effects that account for the electric field dependence of the fine structure splitting^{37}. We hope that our results will stimulate a refinement in understanding of the exciton–nuclear spin interaction.
In conclusion, we report transformlimited optical linewidths from a single semiconductor quantum dot even when measured on second timescales on both X^{0} and X^{1−}. Generally speaking, controlling spin noise is key to operating a quantum dotbased spin qubit^{24,25,38,39,40}. The same factor turns out also to be a key feature in creating a quantum dotbased highfidelity singlephoton source.
Methods
The semiconductor quantum dot sample
The quantum dots are selfassembled using InGaAs in highpurity GaAs and are embedded between an n^{+} back contact (25nm tunnel barrier) and a surface gate^{17,21} (Supplementary Methods and Supplementary Fig. 9). The gate voltage V_{g} determines the electron occupation via Coulomb blockade^{41}.
Resonance fluorescence
The quantum dot optical resonance is driven with a linearly polarized, resonant, continuouswave laser (1 MHz linewidth) focused on to the sample surface. Reflected or scattered laser light is rejected with a darkfield technique using crossed linear polarizations for excitation and detection^{42}. The laser excitation polarization is rotated by an angle of π/4 with respect to the neutral exciton’s linear polarization axes.
Resonance fluorescence is detected with a silicon avalanche photodiode in photoncounting mode. The experiment is not shielded against the earth’s magnetic field, thus B_{min} ∼50 μT. All the experiments were performed with the sample at 4.2 K. Γ is determined by sweeping the laser frequency through the resonance, integrating the counts, typically 100 ms per point.
Additional information
How to cite this article: Kuhlmann, A. V. et al. Transformlimited single photons from a single quantum dot. Nat. Commun. 6:8204 doi: 10.1038/ncomms9204 (2015).
References
Sangouard, N. & Zbinden, H. What are single photons good for? J. Mod. Opt. 59, 1458–1464 (2012).
Michler, P. et al. A quantum dot singlephoton turnstile device. Science 290, 2282–2285 (2000).
Santori, C., Fattal, D., Vučković, J., Solomon, G. S. & Yamamoto, Y. Indistinguishable photons from a singlephoton device. Nature 419, 594–597 (2002).
Shields, A. J. Semiconductor quantum light sources. Nat. Photonics 1, 215–223 (2007).
Nguyen, H. S. et al. Ultracoherent single photon source. Appl. Phys. Lett. 99, 261904 (2011).
Matthiesen, C., Vamivakas, A. N. & Atatüre, M. Subnatural linewidth single photons from a quantum dot. Phys. Rev. Lett. 108, 093602 (2012).
Matthiesen, C. et al. Phaselocked indistinguishable photons with synthesized waveforms from a solidstate source. Nat. Commun. 4, 1600 (2013).
Dalgarno, P. A. et al. Coulomb interactions in single charged selfassembled quantum dots: radiative lifetime and recombination energy. Phys. Rev. B 77, 245311 (2008).
Langbein, W. et al. Radiatively limited dephasing in InAs quantum dots. Phys. Rev. B 70, 033301 (2004).
Gazzano, O. et al. Bright solidstate sources of indistinguishable single photons. Nat. Commun. 4, 1425 (2013).
Bayer, M. & Forchel, A. Temperature dependence of the exciton homogeneous linewidth in In0.60Ga0.40As/GaAs selfassembled quantum dots. Phys. Rev. B 65, 041308 (2002).
Borri, P. et al. Exciton dephasing via phonon interactions in InAs quantum dots: Dependence on quantum confinement. Phys. Rev. B 71, 115328 (2005).
Kroner, M. et al. Resonant saturation laser spectroscopy of a single selfassembled quantum dot. Physica E 40, 1994–1996 (2008).
Ramsay, A. J. et al. Phononinduced Rabifrequency renormalization of optically driven single InGaAs/GaAs quantum dots. Phys. Rev. Lett. 105, 177402 (2010).
Ulrich, S. M. et al. Dephasing of tripletsideband optical emission of a resonantly driven InAs/GaAs quantum dot inside a microcavity. Phys. Rev. Lett. 106, 247402 (2011).
Högele, A. et al. Voltagecontrolled optics of a quantum dot. Phys. Rev. Lett. 93, 217401 (2004).
Houel, J. et al. Probing singlecharge fluctuations at a GaAs/AlAs interface using laser spectroscopy on a nearby InGaAs quantum dot. Phys. Rev. Lett. 108, 107401 (2012).
Prechtel, J. H. et al. Frequencystabilized source of single photons from a solidstate qubit. Phys. Rev. X 3, 041006 (2013).
Hansom, J. et al. Environmentassisted quantum control of a solidstate spin via coherent dark states. Nat. Phys. 10, 725–730 (2014).
Atatüre, M. et al. Quantumdot spinstate preparation with nearunity fidelity. Science 312, 551–553 (2006).
Kuhlmann, A. V. et al. Charge noise and spin noise in a semiconductor quantum device. Nat. Phys. 9, 570–575 (2013).
Warburton, R. J. et al. Giant permanent dipole moments of excitons in semiconductor nanostructures. Phys. Rev. B 65, 113303 (2002).
Braun, P. F. et al. Direct observation of the electron spin relaxation induced by nuclei in quantum dots. Phys. Rev. Lett. 94, 116601 (2005).
Merkulov, I. A., Efros, A. L. & Rosen, M. Electron spin relaxation by nuclei in semiconductor quantum dots. Phys. Rev. B 65, 205309 (2002).
Khaetskii, A. V., Loss, D. & Glazman, L. Electron spin decoherence in quantum dots due to interaction with nuclei. Phys. Rev. Lett. 88, 186802 (2002).
Urbaszek, B. et al. Nuclear spin physics in quantum dots: an optical investigation. Rev. Mod. Phys. 85, 79–133 (2013).
Chekhovich, E. A. et al. Nuclear spin effects in semiconductor quantum dots. Nat. Mater. 12, 494–504 (2013).
Welander, E., Hildmann, J. & Burkard, G. Influence of hyperfine interaction on the entanglement of photons generated by biexciton recombination. Preprint at http://arxiv.org/abs/1409.6521v1 (2014).
Stevenson, R. M. et al. Coherent entangled light generated by quantum dots in the presence of nuclear magnetic fields. Preprint at http://arxiv.org/abs/1103.2969v1 (2015).
Smith, J. M. et al. Voltage control of the spin dynamics of an exciton in a semiconductor quantum dot. Phys. Rev. Lett. 94, 197402 (2005).
Chekhovich, E. A. et al. Pumping of nuclear spins by optical excitation of spinforbidden transitions in a quantum dot. Phys. Rev. Lett. 104, 066804 (2010).
Latta, C. et al. Confluence of resonant laser excitation and bidirectional quantumdot nuclearspin polarization. Nat. Phys. 5, 758–763 (2009).
Stanley, M. J. et al. Dynamics of a mesoscopic nuclear spin ensemble interacting with an optically driven electron spin. Phys. Rev. B 90, 195305 (2014).
Lodahl, P., Mahmoodian, S. & Stobbe, S. Interfacing single photons and single quantum dots with photonic nanostructures. Rev. Mod. Phys. 87, 347–400 (2015).
Klauser, D., Coish, W. A. & Loss, D. Nuclear spin dynamics and zeno effect in quantum dots and defect centers. Phys. Rev. B 78, 205301 (2008).
Ribeiro, H., Maier, F. & Loss, D. Nuclear spin diffusion mediated by heavy hole hyperfine noncollinear interactions. Preprint at http://arxiv.org/abs/1403.0490 (2014).
Bryant, G. W., Malkova, N. & Sims, J. Mechanism for controlling the exciton fine structure in quantum dots using electric fields: manipulation of exciton orientation and exchange splitting at the atomic scale. Phys. Rev. B 88, 161301 (2013).
Xu, X. et al. Coherent population trapping of an electron spin in a single negatively charged quantum dot. Nat. Phys. 4, 692–695 (2008).
Press, D. et al. Ultrafast optical spin echo in a single quantum dot. Nat. Photonics 4, 367–370 (2010).
Warburton, R. J. Single spins in selfassembled quantum dots. Nat. Mater. 12, 483–493 (2013).
Warburton, R. J. et al. Optical emission from a chargetunable quantum ring. Nature 405, 926–929 (2000).
Kuhlmann, A. V. et al. A darkfield microscope for backgroundfree detection of resonance fluorescence from single semiconductor quantum dots operating in a setandforget mode. Rev. Sci. Instrum. 84, 073905 (2013).
Acknowledgements
We acknowledge financial support from NCCR QSIT and from Swiss National Science Foundation (project 200020_156637). We thank Christoph Kloeffel, Daniel Loss, Franziska Maier and Hugo Ribiero for helpful discussions; Sascha Martin and Michael Steinacher for technical support. A.L., D.R. and A.D.W. acknowledge gratefully support from DFG SPP1285 and BMBF QuaHLRep 01BQ1035.
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A.V.K., J.P. and J.H. conducted the experiments and the data analysis; A.L., D.R. and A.D.W. prepared the sample with molecularbeam epitaxy; A.V.K., J.P. and R.J.W. took the lead in writing the paper; R.J.W. supervised the project.
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Supplementary Figures 19, Supplementary Notes 110, Supplementary Methods and Supplementary References. (PDF 762 kb)
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Kuhlmann, A., Prechtel, J., Houel, J. et al. Transformlimited single photons from a single quantum dot. Nat Commun 6, 8204 (2015). https://doi.org/10.1038/ncomms9204
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DOI: https://doi.org/10.1038/ncomms9204
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