Nanostructures quantiques, Propriétés Optique
Domaines de Recherche
L’équipe "Nanostructures Quantiques Propriétés Optiques (NQPO)", conjointement avec l’équipe "Dynamique de spin (SPIN)", développe son activité autour de 6 thèmes :
Plateformes expérimentales
Les activités expérimentale des équipes s’appuient entre autres sur des plateaux expérimentaux d’exception :
| Spectroscopie jusqu’au domaine UV |
Magnéto-optique |
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Nous rejoindre
Plusieurs possibilités de stages, thèses et post-doctorats sont offertes au sein des équipes, parmi lesquelles :
Stage : Thermal sensing at nanoscale with a single spin qubit
Stage : Imaging magnetism at nanoscale with a quantum magnetometer
Stage : Identifying spin qubit defects in wide bandgap materials
Stage : Optical thermotronics
23 Membres
| PERMANENTS | NON PERMANENTS |
Dernières publications
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Strongly Confined Excitons in GaN/AlN Nanostructures with Atomically Thin GaN Layers for Efficient Light Emission in Deep-Ultraviolet 
Auteur(s): Toropov A.a. , Evropeitsev E.a, Nestoklon M. o., Smirnov D.s., Shubina T., Kaibyshev V.kh., Budkin G.v., V. n. jmerik V.n., Nechaev D.v., Rouvimov S., Ivanov Sergey, Gil B.
(Article) Publié:
Nano Letters, vol. p.acs.nanolett.9b03517 (2019)
Ref HAL: hal-02397767_v1
DOI: 10.1021/acs.nanolett.9b03517
Exporter : BibTex | endNote
Résumé: Fascinating optical properties governed by extremely confined excitons have been so far observed in 2D crystals like monolayers of transition metal dichalcogenides. These materials, however, are limited for production by epitaxial methods. Besides, they are not suitable for the development of optoelectronics for the challenging deep-ultraviolet spectral range. Here, we present a single monolayer of GaN in AlN as a heterostructure fabricated by molecular beam epitaxy, which provides extreme 2D confinement of excitons, being ideally suited for light generation in the deep-ultraviolet. Optical studies in the samples, supplemented by a group-theory analysis and first-principle calculations, make evident a giant enhancement of the splitting between the dark and bright excitons due to short-range electron–hole exchange interaction that is a fingerprint of the strongly confined excitons. The practical significance of our results is in the observation of the internal quantum yield of the room-temperature excitonic emission as high as ∼75% at 235 nm
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Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges
Auteur(s): Brault Julien, Matta S., Ngo T. H., Al khalfioui Mohamed, Valvin P., Leroux M, Damilano Benjamin, Korytov Maxim, Brandli Virginie, Vennegues Philippe, Massies Jean, Gil B.
(Article) Publié:
Journal Of Applied Physics, vol. p.205701 (2019)
Ref HAL: hal-02380035_v1
DOI: 10.1063/1.5115593
Exporter : BibTex | endNote
Résumé: AlyGa1−yN quantum dots (QDs) have been grown by molecular beam epitaxy on AlxGa1−xN (0001) using a 2-dimensional–3-dimensional growth mode transition that leads to the formation of QDs. QDs have been grown for Al compositions y varying between 10% and 40%. The influence of the active region design [composition y, QD height, and bandgap difference (ΔEg) between the AlxGa1−xN cladding layer and the AlyGa1−yN QDs] is discussed based on microscopy, continuous wave photoluminescence (PL), and time-resolved PL (TRPL) mea- surements. In particular, increasing y leads to a shift of the QD emission toward shorter wavelengths, allowing covering a spectral range in the UV from 332 nm (UVA) to 276 nm (UVC) at room temperature (RT). The low-temperature (LT) internal quantum efficiency of the QD ensembles was estimated from TRPL experiments at 8 K and values between 11% and 66% were deduced. The highest internal quantum efficiency (IQE)-LT is found for the QDs with higher Al content y. Then, the PL spectrally integrated intensity ratios between RT and LT were measured to estimate the IQE of the samples at RT. The PL ratio is higher for larger ΔEg, for QDs with y of 0.1 or 0.2, and high PL intensity ratios up to 30% were also measured for QDs with larger y of 0.3 and 0.4. RT IQE values between 5% and 20% are deduced for AlyGa1−yN QDs emitting in the 276–308 nm range.
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Entanglement between a Diamond Spin Qubit and a Photonic Time-Bin Qubit at Telecom Wavelength
Auteur(s): Tchebotareva Anna, Hermans Sophie l. n., Humphreys Peter c., Voigt Dirk, Harmsma Peter j., Cheng Lun k., Verlaan Ad l., Dijkhuizen Niels, De jong Wim, Dréau A., Hanson Ronald
(Article) Publié:
Physical Review Letters, vol. 123 p.063601 (2019)
Ref HAL: hal-02379667_v1
DOI: 10.1103/PhysRevLett.123.063601
Exporter : BibTex | endNote
Résumé: We report on the realization and verification of quantum entanglement between a nitrogen-vacancy electron spin qubit and a telecom-band photonic qubit. First we generate entanglement between the spin qubit and a 637 nm photonic time-bin qubit, followed by photonic quantum frequency conversion that transfers the entanglement to a 1588 nm photon. We characterize the resulting state by correlation measurements in different bases and find a lower bound to the Bell state fidelity of ≥ 0.77± 0.03. This result presents an important step towards extending quantum networks via optical fiber infrastructure.
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D. Felbacq gave a lecture on Topological Photonics at the Summer School on Nanophotonics and Metamaterials held in St Petersburg 21-24 June 2016 (http://metalab.ifmo.ru/school/).
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