A quantum dot single photon source

Physica E: Low-dimensional Systems and Nanostructures, 2003

We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode travelling wave is approximately 38%, which is nearly two orders of magnitude higher than for a quantum dot in bulk semiconductor material. At the same time, the probability of having more than one photon in a given pulse is reduced by a factor of seven as compared to light with Poissonian photon statistics.

Journal of Crystal Growth, 2011

We demonstrate electrical pumping of self-assembled InP/Ga 0.51 In 0.49 P quantum dots embedded in a p-in resonant-cavity-diode structure with emission in the red spectral region. A high aluminum containing Al 0.98 Ga 0.02 As layer allows wet thermal oxidation and implementation of a current restricting oxide aperture above the active region. The intended use of these InP-quantum dots in such a resonant-cavity-LED structure as a pulsed electrically driven single-photon emitter was confirmed by measuring the second order intensity correlation function g ð2Þ ðtÞ with a Hanbury-Brown and Twiss type setup. The correlation measurements performed on a single quantum dot ð % 40 KÞ show a clear antibunching behavior (g ð2Þ ð0Þ o 0:24) up to 200 MHz as expected for a single-photon emitter.

2001

Abstract We investigate cavity-quantum electrodynamics (QED) effects in an all-semiconductor nanostructure by tuning a single self-assembled InAs quantum dot (QD) into resonance with a high quality factor microdisk whispering gallery mode (WGM). The stronger temperature dependence of the QD single-exciton (1X) resonance allows us to change the relative energy of the WGM and the 1X transitions by varying the sample temperature.

Applied Physics Letters, 2012

Low temperature, micro-photoluminescence and second-order single photon correlation experiments were performed on individual self-assembled In 0.47 Al 0.34 Ga 0.19 As/Al 0.3 Ga 0.7 As/GaAs quantum dots emitting in the range of 680-780 nm. Emission lines originating from exciton, biexciton, and charge exciton confined in the same dot could be identified. The derived exciton fine structure splitting is ∼ 125 µeV, whereas the biexciton and charge exciton binding energies are ∼ 4 and ∼ 9 meV, respectively. The photon correlation statistics measured for the exciton emission exhibited a clear antibunching with the value of g 2 X−X (0) = 0.30±0.05, confirming unambiguously that such quantum dots act as a true single photon quantum emitters.

2011

We report on the resonant emission in coherently-driven single semiconductor quantum dots. We demonstrate that an ultra-weak non-resonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission quenching, and that the optically-gated quantum dots systematically behave as ideal two-level systems in both regimes of coherent and incoherent resonant emission.

Nature Photonics, 2010

The development of efficient solid-state sources of single photons is a major challenge in the context of quantum communication, optical quantum information processing and metrology 1 . Such a source must enable the implementation of a stable, single-photon emitter, like a colour centre in diamond 2-4 or a semiconductor quantum dot 5-7 . Achieving a high extraction efficiency has long been recognized as a major issue, and both classical solutions 8 and cavity quantum electrodynamics effects have been applied 1,9-12 . We adopt a different approach, based on an InAs quantum dot embedded in a GaAs photonic nanowire with carefully tailored ends 13 . Under optical pumping, we demonstrate a record source efficiency of 0.72, combined with pure single-photon emission. This non-resonant approach also provides broadband spontaneous emission control, thus offering appealing novel opportunities for the development of single-photon sources based on spectrally broad emitters, wavelength-tunable sources or efficient sources of entangled photon pairs. Efficient solid-state sources of single photons (S4P) conventionally feature a quantum dot (QD) integrated in an optical microcavity. At cryogenic temperatures, QDs display spectrally narrow emission lines compatible with the control of spontaneous emission (SE) based on cavity quantum electrodynamics. The Purcell effect, which arises in high Q-factor and low-volume cavities, dynamically funnels most of the QD SE into a single resonant cavity mode 9-12,14 . If the far-field emission diagram of this mode is directional, as for pillar microcavities, the QD SE can be efficiently collected by external optics. Recently, a vertical cavity surface-emitting laser (VCSEL)-like source associated with an optimized collection setup has led to a usable, detected, single-photon flux as high as 4 MHz (ref. 11). However, the efficiency e of the source, defined as the probability of collecting a photon into the first lens of the optical set-up, remains limited to about 0.4 (refs 11,15), in spite of the impressive progress in microcavity figures of merit over recent years . In fact, the far-field emission pattern of high-Q microcavities is very sensitive to fabrication imperfections, which degrade e (ref. 8). Furthermore, this strategy, based on the Purcell effect, is also restricted to quasi-monochromatic emitters and is effective only over the narrow bandwidth of the cavity resonance.

2009

On-demand generation of background-free single photons from a solid-state source Applied Physics Letters 112, 093106 (2018);

Electronics Letters, 2006

A report is presented of a subminiature solid-state emitter structure, which allows electrical pumping of only one single InAs quantum dot (QD) grown in the Stranski-Krastanow mode. The emitter demonstrates a strongly monochromatic polarised emission of a single QD exciton. No other emission is observed across 500 nm. The structure is thus attractive for practical implementation as an effective single photon source for quantum cryptography.

Physical Review Letters, 2005

We report on the observation of the strong coupling regime between a single GaAs quantum dot and a microdisk optical mode. Photoluminescence is performed at various temperatures to tune the quantum dot exciton with respect to the optical mode. At resonance, we observe an anticrossing, signature of the strong coupling regime with a well resolved doublet. The Vacuum Rabi splitting amounts to 400 µeV and is twice as large as the individual linewidths.

Applied Physics Letters, 2009

We demonstrate the deterministic integration of single site-controlled quantum dots (SCQDs) into micropillar cavities. Spatial resonance between single positioned quantum dots (QDs) and GaAs/AlAs micropillar cavities was achieved using cross markers for precise SCQDcavity alignment. Cavity effects are clearly reflected in an enhanced photoluminescence intensity when tuning SCQD emission lines through the fundamental cavity resonance. Single photon emission from a spatially and spectrally coupled SCQD-resonator system is confirmed by photon autocorrelation measurements yielding a g (2) (0) value of 0.12.