Intrinsic and environmental effects on the interference properties of a high-performance quantum dot single-photon source

Gerhardt, S. P.; Iles-Smith, Jake; McCutcheon, Dara P. S.; He, Yu; Unsleber, Sebastian; Betzold, Simon; Gregersen, Niels; Mørk, Jesper; Höfling, Sven; Schneider, Christian

doi:10.1103/physrevb.97.195432

Cited by 23 publications

(25 citation statements)

References 56 publications

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“…The QD couples to both vibrational and electromagnetic environments, which results in the total Hamiltonian H = H S + H S–ph + H S–em + H B . At low temperatures the electron−phonon interaction is dominated by a linear displacement coupling with Hamiltonian , where b k () is the annihilation (creation) operator of phonon mode k with frequency ω k and coupling strength g k 24,47–49 . The electron−phonon coupling is characterised by the spectral density 24 , with coupling strength ζ and cut-off frequency ω c .…”

Section: Methodsmentioning

confidence: 99%

Vibrational enhancement of quadrature squeezing and phase sensitivity in resonance fluorescence

2019

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Vibrational environments are commonly considered to be detrimental to the optical emission properties of solid-state and molecular systems, limiting their performance within quantum information protocols. Given that such environments arise naturally it is important to ask whether they can instead be turned to our advantage. Here we show that vibrational interactions can be harnessed within resonance fluorescence to generate optical states with a higher degree of quadrature squeezing than in isolated atomic systems. Considering the example of a driven quantum dot coupled to phonons, we demonstrate that it is feasible to surpass the maximum level of squeezing theoretically obtainable in an isolated atomic system and indeed come close to saturating the fundamental upper bound on squeezing from a two-level emitter. We analyse the performance of these vibrationally-enhanced squeezed states in a phase estimation protocol, finding that for the same photon flux, they can outperform the single mode squeezed vacuum state.

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Section: Methodsmentioning

confidence: 99%

Vibrational enhancement of quadrature squeezing and phase sensitivity in resonance fluorescence

2019

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“…State-of-the-art experiments have demonstrated that electron-phonon processes play a crucial role in determining the coherence properties of photons emitted from solid-state quantum emitters [23,46,47]. However, developing a theoretical model to accurately account for such processes remains a significant challenge.…”

Section: Electron-phonon Coupling and Its Signatures In The Optical Ementioning

confidence: 99%

Phonon effects in quantum dot single-photon sources

Denning¹,

Iles-Smith²,

Gregersen³

et al. 2019

Opt. Mater. Express

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Semiconductor quantum dots are inevitably coupled to the vibrational modes of their host lattice. This interaction reduces the efficiency and the indistinguishability of singlephotons emitted from semiconductor quantum dots. While the adverse effects of phonons can be significantly reduced by embedding the quantum dot in a photonic cavity, phonon-induced signatures in the emitted photons cannot be completely suppressed and constitute a fundamental limit to the ultimate performance of single-photon sources based on quantum dots. In this paper, we present a self-consistent theoretical description of phonon effects in such sources and describe their influence on the figures of merit. IntroductionSources of single indistinguishable photons are key components in optical quantum information processing [1], and deterministic single-photon sources based on self-assembled semiconductor quantum dots (QDs) have developed significantly over the past few years. QDs can be grown with excellent optical properties, and advances in fabrication of photonic nanostructures have led to demonstrations of bright and coherent single-photon sources [2][3][4][5]. However, the inevitable coupling of the QD to the vibrational phonon modes of the host lattice constitutes a significant challenge [6], which will only be increasingly important as the performance of the sources is pushed from the current state-of-the-art towards the high level necessary for realising large-scale optical quantum computation.There are several figures of merit that characterise the performance of a single photon source. Naturally, the photon number statistics of the emitted light is important. The Hanbury Brown and Twiss second-order correlation function, g (2) (τ), quantifies the probability of simultaneously detecting two photons when evaluated at τ = 0 [8]. Multiphoton components in the emitted light leads to a non-zero value of g (2) (0), which can stem from the excitation process [9][10][11]. Similarly, the efficiency of the source is the probability of sending a single photon into the detection channel when the source is triggered [7]. Another important feature, which characterises the coherence properties of the source, is the indistinguishability of the emitted photons, which is a measure of the degree to which two photons can interfere. The indistinguishability is measured by sending the two photons into the two input ports of a beamsplitter. If the two photons are completely indistinguishable, the Hong-Ou-Mandel effect results in the photons leaving the beamsplitter in the same output port [12]. This effect is a fundamental necessity for linear quantum computing schemes, forming the basis for two-photon gates [13]. Alternatively, the quantum dot can be operated by exciting a biexciton, thereby emitting a polarisation-entangled photon pair [4,14,15]. In this scenario, the entanglement fidelity of the emitted photon pair constitutes an additional figure of merit of the source. Suppressing phonon-assisted photon emission in these pair-sources requires indivi...

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“…Nevertheless, spectral fine-tuning remains the missing tool required to overcome remaining fabrication inaccuracies. Temperature and electrical tuning techniques cause a significant deterioration of the source performance via phonon-induced decoherence [22] and carrier tunneling, respectively [23]. On the other hand, strain tuning techniques allow for reversible shifting of the emitter energies without degrading their optical properties [24,25].…”

Section: Introductionmentioning

confidence: 99%

Optomechanical tuning of the polarization properties of micropillar cavity systems with embedded quantum dots

et al. 2020

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Strain tuning emerged as an appealing tool for tuning of fundamental optical properties of solid-state quantum emitters. In particular, the wavelength and fine structure of quantum dot states can be tuned using hybrid semiconductor-piezoelectric devices. Here, we show how an applied external stress can directly impact the polarization properties of coupled InAs quantum dot-micropillar cavity systems. In our experiment, we find that we can reversibly tune the anisotropic polarization splitting of the fundamental microcavity mode by approximately 60 μeV. We discuss the origin of this tuning mechanism, which arises from an interplay between elastic deformation and the photoelastic effect in our micropillar. Finally, we exploit this effect to tune the quantum dot polarization optomechanically via the polarization-anisotropic Purcell effect. Our work paves the way for optomechanical and reversible tuning of the polarization and spin properties of light-matter-coupled solid-state systems.

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Intrinsic and environmental effects on the interference properties of a high-performance quantum dot single-photon source

Cited by 23 publications

References 56 publications

Vibrational enhancement of quadrature squeezing and phase sensitivity in resonance fluorescence

Vibrational enhancement of quadrature squeezing and phase sensitivity in resonance fluorescence

Phonon effects in quantum dot single-photon sources

Optomechanical tuning of the polarization properties of micropillar cavity systems with embedded quantum dots

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