Par comparaison avec les verres courants que sont les verres à base de silice (oxyde de silicium, SiO2), les verres de chalcogénures sont formés à partir d’éléments tels que le soufre, le sélénium ou le tellure. De cette composition chimique particulière résultent des propriétés optiques exceptionnelles, notamment en termes de transparence à la lumière infrarouge. Ainsi, alors que les verres à base de silice sont transparents jusqu’à des longueurs d’onde de 3 μm environ, les chalcogénures sont transparents jusqu’à 6-10 μm pour les verres au soufre, plus de 11 μm pour les verres au sélénium et jusqu’à 18-25 μm pour les verres riches en tellure. Par ailleurs, comme tous les verres stables, caractérisés par une faible tendance à évoluer vers l’état cristallin, les verres de chalcogénures peuvent être mis en forme par moulage-pressage pour la fabrication de lentilles par exemple, ou par étirage pour l’élaboration de fibres optiques, ou par dépôt pour réaliser des couches minces et des guides d’onde planaires. L’association des possibilités de mise en forme et des propriétés de transmission dans l’infrarouge ouvre un vaste champ d’applications pour ces matériaux issus de la recherche académique : dispositifs infrarouges pour l’imagerie thermique (surveillance, défense, médical), capteurs à fibres optiques ou en optique intégrée pour le diagnostic médical et la surveillance environnementale, interférométrie infrarouge dans le domaine spatial. Certaines de ces applications sont développées au sein d’entreprises créées spécifiquement pour valoriser les résultats obtenus au laboratoire : Umicore IR-Glass (2004), DIAFIR (2011), et SelenOptics (2015).

The development of compact and tunable mid-infrared laser sources in the atmospheric transmission windows presents a major interest for several security and defense applications. Quasi-phase-matched sources in a guided wave configuration are promising solutions to enhance compactness and affordability, because of the reduction in pump power requirements with respect to bulk devices.

Significant progress has been made in this field at Thales Research and Technology along two routes. The first one consists in studying orientation-patterned gallium arsenide (OP-GaAs) waveguides, adapted to fiber laser pumping and to relatively high pump power. The second axis is devoted to the original idea of integrating an antimonide-based laser diode with a gallium antimonide (GaSb) frequency converter in a monolithic component. The goal in both cases is to minimize propagation losses in those waveguides to be able to exploit the whole potential of their non-linear properties. Recent results will be presented and put in perspective with plans for parametric frequency generation and supercontinuum generation in the long wave infrared domain.

The remarkable performance of biomotors has inspired scientists to create synthetic nanoscale machines that mimic the function of these amazing natural systems. Creative research efforts across the globe have led to powerful and versatile man-made nanomachines. Significant improvements in the capabilities of these nanoscale machines have led to greatly enhanced speed and power, motion control, cargo-towing force, versatility, functionality and scope of synthetic nanomotors. The greatly improved capabilities of artificial nanomotors have paved the way to exciting and important new applications. Our team has recently described nanoscale machines capable of ‘writing’ (patterning) nanoscale features, repairing electrical circuits, perform high resolution imaging, generating energy, isolating cancer cells, detecting intracellular targets, or sensing and neutralizing threats. These recent advances and new capabilities will be described, along with future prospects and challenges.

This talk has two parts. In the first part, we take an inspiration from analogy between quantum mechanics and the classical electrodynamics since the dielectric microspheres with coupled whispering gallery modes (WGMs) can be viewed as an example of photonic molecules. We built such molecules by using microspheres with sorted positions of WGM peaks and show that the spectra of supermodes of such molecules have certain features which can be used for identification of their symmetry, number of constituting atoms and topology [1]. We show that these properties can be viewed as “spectral signatures” of various molecules. Excellent agreement was found between measured and calculated spectral signatures.

In the second part, we study coupling of WGMs with graphene flakes deposited on a sidewall surface of high-Q cylindrical resonators. This work was developed in close collaboration with the groups of Anatole Lupu and Maria Tchernycheva at IEF. Our experimental approach is based on manipulation with the positon of WGM orbit excited in a fiber using a side-coupled tapered microfiber. We observed an interesting polarization TE/TM conversion effect in the WGM spectra detected through the microfiber. We believe that this effect represents a novel sensor modality for sensing nanoobjects which has some advantages over conventional modalities based on spectral shift, damping or splitting of the WGM peaks.

229648. [1] Y. Li et al., Whispering Gallery Mode Hybridization in Photonics Molecules, Laser & Phot. Rev. 11, 1600278 (2017).

Bioengineering is based on the use of physical and mathematical principles to deal with biological questions. This strategy was successfully employed to develop new biomaterials or to design novel diagnostic/therapeutic devices. This seminar will describe two bioengineering strategies aiming first at developing new biomaterials for 3-D culture and second at designing a new gene delivery system.

Part1. Modified polyethylenimine–based gene delivery system for Improved biocompatibility.

Part2. In vitro murine ovarian follicle development system based on PEG-hydrogel

The generation of entanglement between more than two particles is a major challenge for all physical realizations. It is required for the realization of many quantum information protocols, including quantum computing. Single photons are one of the most promising realizations of quantum bits (qubits), as they are easily manipulated, preserve their coherence for long times, and information can be stored in their many different degrees of freedom. Up to date, up to ten photons have been entangled in a single state through their polarization degree of freedom. The main difficulties in increasing this number are the elaborated setups required and the low rates of state production. I will present a novel and simple scheme that can in principle generate entanglement between any number of photons in a linear cluster state from a single fixed setup. This scheme combines photons from one source in a single path, but at different times, using an optical delay. It can be extended to create higher-dimensional cluster states, and even arbitrary graph states. Such states are useful for the one-way quantum computer scheme. Results from such a setup using heralded single photons will be presented. States of two and three entangled photons were measured, with good visibilities of their quantum interference. “A resource efficient source of multi-photon polarization entanglement”, E. Megidish, T. Shacham, A. Halevy, L. Dovrat and H.S. Eisenberg, Phys. Rev. Lett. 109, 080504 (2012). “Entanglement swapping between photons that have never coexisted”, E. Megidish, A. Halevy, T. Shacham, T. Dvir, L. Dovrat, and H. S. Eisenberg, Phys. Rev. Lett. 110, 210403 (2013). “Simple source for large linear cluster photonic states”, Y. Pilnyak, N. Aharon, D. Istrati, E. Megidish, A. Retzker, H. S. Eisenberg, Phys. Rev. A 95, 022304 (2017)

Interactions between light and matter lie at the heart of optical communication and information technology. Nanophotonic devices enhance light-matter interactions by confining photons to small mode volumes, enabling optical information processing at low energies. In the strong coupling regime, these interactions are sufficiently large that a single photon creates a nonlinear response in a single atomic system. Such single-photon nonlinearities are highly desirable for quantum information processing applications where atoms serve as quantum memories and photons act as carriers of quantum information. In this talk I will discuss our effort to develop and coherently control strongly coupled nanophotonic devices using quantum dots coupled to photonic crystals. Quantum dots are semiconductor “artificial atoms” that can act as efficient photon emitters and stable quantum memories. By embedding them in a photonic crystal cavity that spatially confines light to less than a cubic wavelength we can attain the strong coupling regime. This device platform provides a pathway towards compact integrated quantum devices on a semiconductor chip that could serve as basic components of quantum networks and distributed quantum computers. I will discuss our demonstration of a quantum transistor, the fundamental building block for quantum computers and quantum networks, using a single electron spin in a quantum dot [1, 2]. I will then describe a realization of a new cavity QED approach to measure the state of a spin all-optically. This technique enables efficient spin readout even when the spin has a poor cycling transition. Finally, I will discuss our recent effort to extend our results into the telecommunication wavelengths, and to improve the efficiency and scalability of the structure in order to attain integrated multi-dot devices on a single chip. Biography Edo Waks is a professor in the Department of Electrical and Computer Engineering at the University of Maryland, College Park. He is also a member of the Joint Quantum Institute (JQI), a collaborative effort between the University of Maryland and NIST, Gaithersburg, dedicated to the study of quantum coherence. Waks received his B.S. and M.S. from Johns Hopkins University, and his Ph.D. from Stanford University. He is a recipient of a Presidential Early Career Award for Scientists and Engineers (PECASE), an NSF CAREER award, and ARO Young Investigator Award for the investigation of interactions between quantum dots and nanophotonic structures. His current work focuses coherent control and manipulation semiconductor quantum dots, and their interactions with photonic crystal devices for creating strong atom-photon interactions.

Après avoir défini ce que la loi entend par traitement de données à caractère personnel nous allons aborder quelques grands principes à respecter lors de la mise en oeuvre de ces derniers. Un échange est prévu afin de pouvoir poser des questions pratiques.