Polariton lasing in high-quality Selenide-based micropillars in the strong coupling regime

We have designed and fabricated all-epitaxial ZnSe-based optical micropillars exhibiting the strong coupling regime between the excitonic transition and the confined optical cavity modes. At cryogenic temperatures, under non-resonant pulsed optical excitation, we demonstrate single transverse mode polariton lasing operation in the micropillars. Owing to the high quality factors of these microstructures, the lasing threshold remains low even in micropillars of the smallest diameter. We show that this feature can be traced back to a sidewall roughness grain size below 3 nm, and to suppressed in-plane polariton escape.Comment: 5 pages, 3 figure

Long range correlations in a 97% excitonic one-dimensional polariton condensate

We report on the realization of an out-of-equilibrium polariton condensate under pulsed excitation in a one-dimensional geometry. We observe macroscopic occupation of a polaritonic mode with only 3% photonic fraction, and a nature strikingly close to that of a bare exciton condensate. With the help of this tiny photonic fraction, the condensate is found to display first-order coherence over distances as large as 10 microns. Based on a driven-dissipative mean field model, we find that the correlations length is limited by the effects of a shallow disorder under non-equilibrium conditions.Comment: 5 pages, 3 figure

Ville à lire, service de prêt à domicile des médiathèques de Villeurbanne

Créé en 1998 à la demande de la collectivité (dispositif E mplois jeunes), le prêt à domicile contribue à la lutte contre l\u27exclusion et au développement de la lecture publique en direction de publics empêchés

Exciton-polaritons gas as a nonequilibrium coolant

Using angle-resolved Raman spectroscopy, we show that a resonantly excited ground-state exciton-polariton fluid behaves like a nonequilibrium coolant for its host solid-state semiconductor microcavity. With this optical technique, we obtain a detailed measurement of the thermal fluxes generated by the pumped polaritons. We thus find a maximum cooling power for a cryostat temperature of $50$K and below where optical cooling is usually suppressed, and we identify the participation of an ultrafast cooling mechanism. We also show that the nonequilibrium character of polaritons constitutes an unexpected resource: each scattering event can remove more heat from the solid than would be normally allowed using a thermal fluid with normal internal equilibration.Comment: 5 pages, 3 figures + supplemental materia

A DfT Architecture for Asynchronous Networks-on-Chip

International audienceThe Networks-on-Chip (NoCs) paradigm is emerging as a solution for the communication of SoCs. Many NoC architecture propositions are presented but few works on testing these network architectures. To test the SoCs, the main challenge is to reach into the embedded cores (i.e, the IPs). In this case, the DFT techniques that integrate test architectures into the SoCs to ease the test of these SoCs are really favoured. In this paper, we present a new methodology for testing NoC architectures. A modular, generic, scalable and configurable DFT architecture is developed in order to ease the test of NoC architectures. The target of this test architecture is asynchronous NoC architectures that are implemented in GALS systems. The proposed architecture is therefore named ANOC-TEST and is implemented in QDI asynchronous circuits. In addition, this architecture can be used to test the computing resources of the networked SoCs. Some initial results and conclusions are also give

TOWARDS A DATA MODEL FOR PLM APPLICATION IN BIO-MEDICAL IMAGING

International audienceBio-Medical Imaging (BMI) is currently confronted to data issues similar to those of the manufacturing industry twenty years ago. In particular, the need for data sharing and reuse has never been so strong to foster major discoveries in neuroimaging. Some data management systems have been developed to meet the requirements of BMI large-scale research studies. However, many efforts to integrate the data provenance along a research study, from the specifications to the published results, are to be done. Product Lifecycle Management (PLM) systems are designed to comply with manufacturing industry expectations of providing the right information at the right time and in the right context. Consequently PLM systems are proposed to be relevant for the management of BMI data. From a need analysis led with the GIN research group, the BMI-LM data model is designed: it is PLM-oriented, generic (enabling the management of many types of data such as imaging, clinical, psychology or genetics), flexible (enabling users’ customisation) and it covers the whole stages of a BMI study from specifications to publication. The test implementation of the BMI-LM model into a PLM system is detailed. The preliminary feed-back of the GIN researchers is discussed in this paper: the BMI-LM data model and the PLM concepts are relevant to manage BMI data, but PLM systems interfaces are unsuitable for BMI researchers

A strange Evans syndrome: a case report

Hepatic angiosarcoma is a rare malignant vascular tumor, which accounts for up to 2% of all primary liver tumors. The most frequent symptoms on presentation are weight loss, weakness and abdominal pain. Diagnosis of diffuse hepatic angiosarcoma can be challenging. We report an original case of diffuse liver angiosarcoma revealed by haematological abnormalities initially diagnosed as an Evans syndrome. Anaemia and thrombocytopenia are rarely the first manifestations of this pathology. They are explained by combination of several mechanisms. Diagnosis of diffuse liver angiosarcoma can be extremely difficult and physicians should be aware of these presentation

How to Implement an Asynchronous Test Wrapper for Network-on-Chip Nodes

International audienceThe Network-on-Chip (NoC) paradigm is currently known as an alternative solution for the on chip communication in the next SoC generation, especially, asynchronous NoCs. One of the challenges for asynchronous NoC-based systems design is testing asynchronous network architectures for manufacturing defects. To improve the testability of asynchronous NoCs, we have developed a scalable and configurable asynchronous Design-for-Test (DfT) architecture. In this architecture, each asynchronous network node is surrounded by an asynchronous test wrapper and the network communication channels are reused as a high-speed Test Access Mechanism (TAM). This architecture is designed to test all network elements (routers, communication channels), but it can also be used to test computational resources. In this paper, we introduce how to realize and implement the test wrapper in Quasi Delay Insensitive (QDI) asynchronous logic style. The validation and experimental results are also presented

A three-level signature by graph for Reverse Engineering of mechanical assemblies

Several approaches exist to provide Reverse Engineering solutions on mechanical parts. Mechanical assemblies and the expertise information retrieved at the same time with the model geometry are not really taken into account in the literature. Thus, the main challenge of this contribution is to propose a methodology to retrieve the Digital Mock-Up of a mechanical assembly from its meshed data (from digitalization). The output DMU consists of expertise information and parameterized CAD models. The methodology proposed relies on a signature by a three-level graph. It enables to provide an adequate level of details by identifying the corresponding functional surfaces in meshed data. The first-level graph is a connectivity graph; the intermediate level is the same as the first with the geometric type of face added to each node (plane, cylinder and sphere) and the deepest level corresponds to a precedence graph. This one provides information such as functional surfaces and position between them (perpendicularity, coaxiality etc.). The solutions developed and the results are presented in this paper. The methodology is illustrated thanks to an industrial use-case with a scan of an assembly with a connecting rod and a piston. The conclusion and perspectives will complete this paper

Knowledge capture and reuse through expert’s activity monitoring in engineering design

This paper deals with artificial intelligence driven product engineering support. Many software systems are available to support the product lifecycle, especially during product design, such as CAD, PDM, CAE, SDM, etc. Most product development process is performed using these systems, which through their rich user interfaces allow skilled professionals to express their expertise and knowledge using the tools and functions the software is willing to provide them. At the end of the day, the result of their work is a model, built through a user interface, and stored in a repository. The goal of our research is to reverse engi-neer the user’s knowledge by analysing his/her actions with the software system, based on the assumption that the process will itself be meta-knowledge driven and that we will focus on engineering software which provide semantically rich user interfaces. The aim of this paper is to investigate the idea of building reusa-ble expert knowledge from actions on engineering software user interfaces. It first outlines existing works from different fields and identifies remaining issues. It then suggest an approach to address these issues and put together an operational system