Laboratoire Pierre Aigrain

LPA

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ENS Paris

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UFR Physique

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UMR

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Université Paris Diderot, CNRS, UPMC

Présentation

Le Laboratoire Pierre Aigrain (LPA) est concerné par divers aspects fondamentaux de la nano-physique : boîtes quantiques et microcavités de semiconducteurs, structures conductrices mésoscopiques, films minces supraconducteurs, molécules uniques carbonées (nanotubes) ou biologiques (ADN). Il étudie d’un point de vue expérimental et théorique ces nano-objets dont les possibilités d’application couvrent des domaines aussi diversifiés que l’optoélectronique, l’information quantique, l’électronique moléculaire, la reconnaissance électronique des molécules biologiques. Il travaille en particulier grâce à un réseau de collaborations nationales et internationales (CNRS/CRHEA Valbonne, CEA/CNRS Grenoble, CEA/Saclay, Universités d’Orsay, de Tokyo, de Californie à Santa Barbara, Institut Pasteur, Département de biologie de l’ENS, Max-Planck Institüt, LCR-Thalès, Alcatel, Motorola), sans oublier son partenaire privilégié, le Laboratoire de Photonique et Nanostructures de Marcoussis.

Les techniques expérimentales sont celles de la spectroscopie optique classique ou laser, linéaire ou non linéaire, des mesures de transport électrique en régime continu ou radiofréquence, des mesures de force à l’échelle du piconewton. S’y ajoute une importante activité théorique.

Le Laboratoire compte une soixantaine de personnes: chercheurs, enseignant-chercheurs, ingénieurs et techniciens, doctorants, post-doctorants. Il est divisé en six équipes expérimentales auxquelles s’ajoutent l’équipe théorique, une équipe d'instrumentation et un service administratif. Il participe activement aux activités d'enseignement de l'ENS et des universités Paris Diderot et Paris 6.

Jean-Marc Berroir

Thèmes de recherche

Biophysique

- Physique du vivant : Moteurs moléculaires et interactions ADN-protéines à l'échelle de la molécule unique: mesures de force par piège optique et pince magnétique

- Physique de l'ADN : Approches physiques de la biologie moléculaire: manipulation de molécules uniques, mesures de force par pièges optiques et mesures électroniques

Propriété électronique des nano-objets

- Optique cohérente et non-linéaire : Nouveaux Matériaux et microcavités, Propriétés opto-électroniques des hétérostructures

- Infra-rouge lointain : Magnétospectroscopie des nanostructures dans l'infrarouge lointain

Théorie

- Propriétés électroniques des nano-objets

- Systèmes fortement corrélés et mésoscopiques : effet Hall quantique fractionnaire, liquides de Luttinger, magnétisme en basses dimensions

Physique Mésoscopique - Transport

- Physique Mésoscopique : transport mésoscopique hyperfréquence, transport électronique à l'échelle atomique

- Transport : Dynamique du paramètre d'ordre supraconducteur et des vortex

[hal-04696792] Widely tunable single-photon source from a carbon nanotube in the Purcell regime

Date: 13 9 月 2024 - 13:39

Desc: The narrow emission of a single carbon nanotube at low temperature is coupled to the optical mode of a fiber microcavity using the built-in spatial and spectral matching brought by this flexible geometry. A thorough cw and time-resolved investigation of the very same emitter both in free space and in cavity shows an efficient funneling of the emission into the cavity mode together with a strong emission enhancement corresponding to a Purcell factor of up to 5. At the same time, the emitted photons retain a strong sub-Poissonian statistics. By exploiting the cavity feeding effect on the phonon wings, we locked the emission of the nanotube at the cavity resonance frequency, which allowed us to tune the frequency over a 4 THz band while keeping an almost perfect antibunching. By choosing the nanotube diameter appropriately, this study paves the way to the development of carbon-based tunable single-photon sources in the telecom bands

[hal-02346247] Synthesis of Loose Nanodiamonds Containing Nitrogen-Vacancy Centers for Magnetic and Thermal Sensing

Date: 4 11 月 2019 - 22:23

Desc: [...]

[hal-02386444] TGFβi is involved in the chondrogenic differentiation of mesenchymal stem cells and is dysregulated in osteoarthritis

Date: 25 11 月 2020 - 11:55

Desc: Objective: Transforming growth factor-b (TGFb) is a major regulator of cartilage homeostasis and its deregulation has been associated with osteoarthritis (OA). Deregulation of the TGFb pathway in mesenchymal stem cells (MSCs) has been proposed to be at the onset of OA. Using a secretome analysis, we identified a member of the TGFb family, TGFb-induced protein (TGFbi or bIGH3), expressed in MSCs and we investigated its function and regulation during OA. Design: Cartilage, bone, synovium, infrapatellar fat pad and bone marrow-MSCs were isolated from patients with OA or healthy subjects. Chondrogenesis of BM-MSCs was induced by TGFb3 in micropellet culture. Expression of TGFbi was quantified by RT-qPCR, ELISA or immunohistochemistry. Role of TGFbi was investigated in gain and loss of function experiments in BM-MSCs and chondrocytes. Results: TGFbi was up-regulated in early stages of chondrogenesis and its knock-down in BM-MSCs resulted in the down-regulation of mature and hypertrophic chondrocyte markers. It likely occurred through the modulation of adhesion molecules including integrin (ITG)b1, ITGb5 and N-cadherin. We also showed that TGFbi was upregulated in vitro in a model of OA chondrocytes, and its silencing enhanced the hypertrophic marker type X collagen. In addition, TGFbi was up-regulated in bone and cartilage from OA patients while its expression was reduced in BM-MSCs. Similar findings were observed in a murine model of OA. Conclusions: Our results revealed a dual role of TGFbi during chondrogenesis and pointed its deregulation in OA joint tissues. Modulating TGFbi in BM-MSCs might be of interest in cartilage regenerative medicine.

[hal-04686246] Author Correction: Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing

Date: 4 9 月 2024 - 00:17

Desc: The original version of this Article omitted the following from the Acknowledgements: Z. Leghtas' primary affiliation is Centre Automatique et Systèmes, Mines ParisTech. This has been corrected in both the PDF and HTML versions of the Article.

[hal-04687159] Beam shaping in high-power broad-area quantum cascade lasers using optical feedback

Date: 4 9 月 2024 - 11:21

Desc: Broad-area quantum cascade lasers with high output powers are highly desirable sources for various applications including infrared countermeasures. However, such structures suffer from strongly deteriorated beam quality due to multimode behavior, diffraction of light and self-focusing. Quantum cascade lasers presenting high performances in terms of power and heat-load dissipation are reported and their response to a nonlinear control based on optical feedback is studied. Applying optical feedback enables to efficiently tailor its near-field beam profile. The different cavity modes are sequentially excited by shifting the feedback mirror angle. Further control of the near-field profile is demonstrated using spatial filtering. The impact of an inhomogeneous gain as well as the influence of the cavity width are investigated. Compared to existing technologies, that are complex and costly, beam shaping with optical feedback is a more flexible solution to obtain high-quality mid-infrared sources.