Single pairs of time-bin-entangled photons

Versteegh, Marijn A. M.; Reimer, Michael E.; Berg, A. van den; Juška, Gediminas; Dimastrodonato, V.; Gocalinska, Agnieszka; Pelucchi, E.; Zwiller, Val

doi:10.1103/physreva.92.033802

Cited by 35 publications

(18 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Beside the near-optimal level of entanglement and indistinguishability of the emitted photons, our QDs emit in the spectral range of absorption resonances of rubidium atoms, a system which has proven its potential as long-lived and efficient quantum memory 45 . Moreover, the availability of downconversion techniques 46 in combination with methods to convert polarization entanglement into time-bin entanglement 47 48 make our QDs suited for quantum communication at telecom wavelengths. A key ingredient to achieve high single-photon purity, high two-photon interference and high level of entanglement is the two-photon resonant excitation.…”

Section: Discussionmentioning

confidence: 99%

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

et al. 2017

View full text Add to dashboard Cite

The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g(2)(0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies.

show abstract

Section: Discussionmentioning

confidence: 99%

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In particular, intense research efforts using InAs semiconductor QDs have enabled the generation of triggered photon pairs at * mullera@usf.edu high rates and under electric pump in a monolithic semiconductor chip with a high degree of polarization entanglement [23,24]. Recently it was shown that such polarization entanglement can be converted into time-bin entanglement, with the polarization entanglement derived from the biexciton/exciton three-level system [25,26].…”

mentioning

confidence: 99%

Franson Interference Generated by a Two-Level System

2017

View full text Add to dashboard Cite

We report a Franson interferometry experiment based on correlated photon pairs generated via frequency-filtered scattered light from a near-resonantly driven two-level semiconductor quantum dot. In contrast to spontaneous parametric down conversion and four-wave mixing, this approach can produce single pairs of correlated photons. We have measured a Franson visibility as high as 66%, which goes beyond the classical limit of 50% and approaches the limit of violation of Bell's inequalities (70.7%).Introduction-Entanglement is perhaps the most intriguing of all physical phenomena, and was famously challenged by Einstein, Podolsky and Rosen (EPR) in 1935 [1]. The EPR paradox led to Bell's inequalities [2] which were since tested by numerous experiments [3] including recent "loophole-free" tests [4][5][6] that have conclusively demonstrated that entanglement cannot be explained using local hidden variable theories.Most experiments have employed photons that are entangled in the energy and polarization degrees of freedom [7][8][9][10]. However, this method is known to be sensitive to polarization mode dispersion in optical fibers [11]. As an alternative, entanglement in the time-energy basis may be employed, wherein quantum information is encoded in the arrival time of photons, and long-distance fiber transmission over 300 km is possible [12]. The approach of using time-energy entangled photons was first formulated by Franson, with photon pairs created in an atomic decay process and two unbalanced interferometers [13]. Franson-type experiments have stimulated a plethora of research activities and have been extensively used for Bell tests in quantum optics [14][15][16].Today, entangled photon pairs for Franson experiments are primarily produced via spontaneous parametric down conversion (SPDC) or four-wave mixing (FWM), following two main methods. In time-energy experiments [17,18], a nonlinear medium is pumped by a continuous monochromatic laser and emission times of the photons have an uncertainty equal to the coherence time of the pump laser. On the other hand in time-bin experiments [14,19], a nonlinear medium is pumped by pulses that have previously passed through an unbalanced interferometer, leading to a "which-path" ambiguity in emission time. However, either method provides a nondeterministic pair generation, leading to limitations on the accuracy and security of quantum communication.Single-photon sources, based on single atoms, ions, impurity centers and quantum dots (QDs) [20], have emerged as alternatives [21,22], emitting no more than a single pair during any given cascade decay. In particular, intense research efforts using InAs semiconductor QDs have enabled the generation of triggered photon pairs at

show abstract

“…Direct timebin-encoded entanglement generation from quantum dots has the advantage that larger FSSs are acceptable [37] but this scheme cannot produce true on-demand entangled pairs without the addition of a metastable state [37,38] and is technically demanding due to the need for phase control between the early and late photons, which can only be achieved with resonant two-photon excitation [39,40]. Alternatively, in the approach favored here, qubit transcoder setups using asymmetric Mach-Zehnder interferometers (AMZIs) can be used to create timebin-entangled photons from polarization-entangled ones [41,42]; however, demonstrations of this principle using C-band QDs are still outstanding.…”

Section: Introductionmentioning

confidence: 99%