Nature 492, 86 (2012)

Controlled-reflectance surfaces with film-coupled colloidal nanoantennas

Antoine Moreau, Cristian Ciracì, Jack J. Mock, Ryan T. Hill, Qiang Wang, Benjamin J. Wiley, Ashutosh Chilkoti,David R. Smith

Efficient and tunable absorption is essential for a variety of applications, such as designing controlled-emissivity surfaces for thermophotovoltaic devices, tailoring an infrared spectrum for controlled thermal dissipation and producing detector elements for imaging. Metamaterials based on metallic elements are particularly efficient as absorbing media, because both the electrical and the magnetic properties of a metamaterial can be tuned by structured design. So far, metamaterial absorbers in the infrared or visible range have been fabricated using lithographically patterned metallic structures, making them inherently difficult to produce over large areas and hence reducing their applicability. Here we demonstrate a simple method to create a metamaterial absorber by randomly adsorbing chemically synthesized silver nanocubes onto a nanoscale-thick polymer spacer layer on a gold film, making no effort to control the spatial arrangement of the cubes on the film. We show that the film-coupled nanocubes provide a reflectance spectrum that can be tailored by varying the geometry (the size of the cubes and/or the thickness of the spacer). Each nanocube is the optical analogue of a grounded patch antenna, with a nearly identical local field structure that is modified by the plasmonic response of the metal’s dielectric function, and with an anomalously large absorption efficiency that can be partly attributed to an interferometric effect. The absorptivity of large surface areas can be controlled using this method, at scales out of reach of lithographic approaches (such as electron-beam lithography) that are otherwise required to manipulate matter on the nanoscale.

Nature Physics, 8, 724 (2012)

Half-solitons in a polariton quantum fluid behave like magnetic monopoles

R. Hivet, H. Flayac, D. D. Solnyshkov, D. Tanese, T. Boulier, D. Andreoli, E. Giacobino, J. Bloch, A. Bramati, G. Malpuech & A. Amo

This experimental and theoretical work results from a collaboration between LKB and LPN in Paris and our team in Clermont. An analogue of a magnetic monopole is now observed in a condensed state of light–matter hybrid particles known as cavity polaritons. Spin-phase excitations of the polariton fluid are accelerated along the cavity under the influence of a magnetic field—just as if they were single magnetic charges. See Also about this article: Nature Physics News and Views : Magnetic monopoles: Magnetricity near the speed of light Steven T. Bramwell Nature Physics 8, 703 (2012).

Phys. Rev. Lett. 108, 037401 (2012)

Mesoscopic Self-Collimation and Slow Light in All-Positive Index Layered Photonic Crystals

Julien Arlandis, Emmanuel Centeno, Rémi Pollès, Antoine Moreau, Julien Campos, Olivier Gauthier-Lafaye, and Antoine Monmayrant

This theoretical work is the result of a collaboration between our team and the LAAS in Toulouse. We demonstrate a mesoscopic self-collimation effect in photonic crystal superlattices consisting of a periodic set of all-positive index 2D photonic crystal and homogeneous layers. We develop an electromagnetic theory showing that diffraction-free beams are observed when the curvature of the optical dispersion relation is properly compensated for. This approach allows us to combine slow-light regime together with self-collimation in photonic crystal superlattices presenting an extremely low filling ratio in air.

Phys. Rev. Lett. 108, 036405 (2012)

Backscattering Suppression in Supersonic 1D Polariton Condensates

D. Tanese, D. D. Solnyshkov, A. Amo, L. Ferrier, E. Bernet-Rollande, E. Wertz, I. Sagnes, A. Lemaître, P. Senellart, G. Malpuech, and J. Bloch

This experimental and theoretical work is the result of a collaboration between LPN in Paris and the N2 team in Clermont. We investigate the effect of disorder on the propagation of one-dimensional polariton condensates in semiconductor microcavities. We observe a strong suppression of the backscattering produced by the imperfections of the structure when increasing the condensate density. This suppression occurs in the supersonic regime and is simultaneous to the onset of parametric instabilities which enable the “hopping” of the condensate through the disorder. Our results evidence a new mechanism for the strong scattering reduction of polaritons at high speeds.

Phys. Rev. Lett. 106, 126401 (2012)

Interactions in Confined Polariton Condensates

Lydie Ferrier, Esther Wertz, Robert Johne, Dmitry D. Solnyshkov, Pascale Senellart, Isabelle Sagnes, Aristide Lemaître, Guillaume Malpuech, and Jacqueline Bloch

This experimental and theoretical work is the result of a collaboration between LPN in Paris and the N2 team in Clermont. We investigate the effect of interactions in zero-dimensional polariton condensates. The shape of the condensate wave function is shown to be modified by repulsive interactions with the reservoir of uncondensed excitons. In large micropillar cavities, when uncondensed excitons are located at the center, the condensate is ejected toward the pillar edges. The same effect results in the generation of optical traps in wire cavities. Once polariton condensates are spatially separated from the excitonic reservoir, spectral signatures of polariton-polariton interactions within the condensate are evidenced.

Phys. Rev. Lett. 109, 216404 (2012)

Propagation and Amplification Dynamics of 1D Polariton Condensates

E. Wertz, A. Amo, D. D. Solnyshkov, L. Ferrier, T. C. H. Liew, D. Sanvitto, P. Senellart, I. Sagnes, A. Lemaître, A. V. Kavokin, G. Malpuech, and J. Bloch

The dynamics of propagating polariton condensates in one-dimensional microcavities is investigated through time resolved experiments. We find a strong increase in the condensate intensity when it travels through the nonresonantly excited area. This amplification is shown to come from bosonic stimulated relaxation of reservoir excitons into the polariton condensate, allowing for the repopulation of the condensate through nonresonant pumping. Thus, we experimentally demonstrate a polariton amplifier with a large band width, opening the way towards the transport of polaritons with high densities over macroscopic distances.

Thomas Weiss (N2 PhD student) under the supervision of Nikolay Gippius and Gérard Granet has obtained the best thesis prize of DFH/UFA which has been delivered to him by Mrs. Ambassador of Germany in Paris.

Hugo Flayac (N2 PhD student), supervised by G. Malpuech, has obtained the Best Young Researcher Award of Clermont-Ferrand (Prix Jeune Chercheur 2013).

Nature Physics 9, 275 (2013)

Macroscopic quantum self-trapping and Josephson oscillations of exciton-polaritons

M. Abbarchi, A. Amo, V.G. Sala, D.D. Solnyshkov, H. Flayac, L. Ferrier, I. SAgnes, E. Galopin, A. Lemaitre, G. Malpuech, J. Bloch

The coupling of two macroscopic quantum states through a tunnel barrier gives rise to Josephson phenomena such as Rabi oscillations, the a.c. and d.c. effects, or macroscopic self-trapping, depending on whether tunnelling or interactions dominate. Nonlinear Josephson physics was first observed in superfluid helium and atomic condensates, but it has remained inaccessible in photonic systems because it requires large photon–photon interactions. Here we report on the observation of nonlinear Josephson oscillations of two coupled polariton condensates confined in a photonic molecule formed by two overlapping micropillars etched in a semiconductor microcavity. At low densities we observe coherent oscillations of particles tunnelling between the two sites. At high densities, interactions quench the transfer of particles, inducing the macroscopic self-trapping of polaritons in one of the micropillars. The finite lifetime results in a dynamical transition from self-trapping to oscillations with π phase. Our results open the way to the experimental study of highly nonlinear regimes in photonic systems, such as chaos or symmetry-breaking bifurcations.

Nature Communications 4, 2313 (2013)

Polariton condensation in solitonic Gap states in a one dimensional periodic potential

D. Tanese, H. Flayac, D. Solnyshkov, A. Amo, A. Lemaitre, E. Galopin, R. Braive, P. Senellart, I. Sagnes, G. Malpuech, J. Bloch

Manipulation of nonlinear waves in artificial periodic structures leads to spectacular spatial features, such as generation of gap solitons or onset of the Mott insulator phase transition. Cavity exciton–polaritons are strongly interacting quasiparticles offering large possibilities for potential optical technologies. Here we report their condensation in a one-dimensional microcavity with a periodic modulation. The resulting mini-band structure dramatically influences the condensation process. Contrary to non-modulated cavities, where condensates expand, here, we observe spontaneous condensation in localized gap soliton states. Depending on excitation conditions, we access different dynamical regimes: we demonstrate the formation of gap solitons either moving along the ridge or bound to the potential created by the reservoir of uncondensed excitons. We also find Josephson oscillations of gap solitons triggered between the two sides of the reservoir. This system is foreseen as a building block for polaritonic circuits, where propagation and localization are optically controlled and reconfigurable.

Phys. Rev. Lett. 110, 196406 (2013)

From Excitonic to Photonic Polariton Condensate in a ZnO-Based Microcavity

Feng Li, L. Orosz, O. Kamoun, S. Bouchoule, C. Brimont, P. Disseix, T. Guillet, X. Lafosse, M. Leroux, J. Leymarie, M. Mexis, M. Mihailovic, G. Patriarche, F. Réveret, D. Solnyshkov, J. Zuniga-Perez, and G. Malpuech

We report exciton-polariton condensation in a new family of fully hybrid ZnO-based microcavity demonstrating the best-quality ZnO material available (a bulk substrate), a large quality factor (∼4000) and large Rabi splittings (∼240  meV). Condensation is achieved between 4 and 300 K and for excitonic fractions ranging between 17% and 96%, which corresponds to a tuning of the exciton-polariton mass, lifetime, and interaction constant by 1 order of magnitude. We demonstrate mode switching between polariton branches allowing, just by controlling the pumping power, to tune the photonic fraction by a factor of 4.

Phys. Rev. Lett. 110, 236601 (2013)

Realization of a Double-Barrier Resonant Tunneling Diode for Cavity Polaritons

H. S. Nguyen, D. Vishnevsky, C. Sturm, D. Tanese, D. Solnyshkov, E. Galopin, A. Lemaître, I. Sagnes, A. Amo, G. Malpuech, and J. Bloch

We report on the realization of a double-barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We show that a nonresonant beam can be used as an optical gate and can control the device transmission. Finally, we evidence distortion of the transmission profile when going to the high-density regime, signature of polariton-polariton interactions. Editor's Suggestion + Viewpoint

Phys. Rev. Lett. 110, 246404 (2013)

Skyrmion Formation and Optical Spin-Hall Effect in an Expanding Coherent Cloud of Indirect Excitons

D. V. Vishnevsky, H. Flayac, A. V. Nalitov, D. D. Solnyshkov, N. A. Gippius, and G. Malpuech

We provide a theoretical description of the polarization pattern and phase singularities experimentally evidenced recently in a condensate of indirect excitons [H. High et al., Nature 483, 584 (2012)]. We show that the averaging of the electron and hole orbital motion leads to a comparable spin-orbit interaction for both types of carriers. We demonstrate that the interplay between a radial coherent flux of bright indirect excitons and the Dresselhaus spin-orbit interaction results in the formation of spin domains and of topological defects similar to Skyrmions. We reproduce qualitatively all the features of the experimental data and obtain a polarization pattern as in the optical spin-Hall effect despite the different symmetry of the spin-orbit interactions.

Phys. Rev. Lett. 110, 035303 (2013)

Topological Wigner Crystal of Half-Solitons in a Spinor Bose-Einstein Condensate

H. Terças, D. D. Solnyshkov, and G. Malpuech

We consider a one-dimensional gas of half-solitons in a spinor Bose-Einstein condensate. We calculate the topological interaction potential between the half-solitons. Using a kinetic equation of the Vlasov-Boltzmann type, we model the coupled dynamics of the interacting solitons. We show that the dynamics of the system in the gaseous phase is marginally stable and spontaneously evolves toward a Wigner crystal.

Phys. Rev. Lett. 110, 016404 (2013)

Transmutation of skyrmions to half-solitons driven by the nonlinear optical spin-Hall effect

H. Flayac, D. Solnyshkov, I.A. Shelykh, G. Malpuech.

We show that the spin domains, generated in the linear optical spin Hall effect by the analog of spin-orbit interaction for exciton polaritons, are associated with the formation of a Skyrmion lattice. In the nonlinear regime, the spin anisotropy of the polariton-polariton interactions results in a spatial compression of the domains and in a transmutation of the Skyrmions into oblique half-solitons. This phase transition is associated with both the focusing of the spin currents and the emergence of a strongly anisotropic emission pattern.

Compatibilité Electromagnétique (CEM)

Présentation

Le groupe Compatibilité Electromagnétique développe des modèles numériques déterministes et stochastiques pour la résolution de problèmes de propagation, rayonnement et diffraction, appliqués aux cas de systèmes complexes réels : réseaux de lignes multifilaires de transmission, structures tridimensionnelles. Ces travaux théoriques sont complétés par des activités expérimentales s’appuyant sur une Chambre Réverbérante à Brassage de Modes (CRBM) de grandes dimensions (6,40m X 7,60m X 3,50m) dont s’est doté le laboratoire.

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Nanophotonique et nanostructures (N2)

Présentation

Théorie et spectroscopie de nanostructures de semiconducteurs, électromagnétisme optique.

Nous étudions théoriquement et expérimentalement les microcavités en régime de couplage fort lumière-matière. La condensation de Bose-Einstein des excitons-polaritons et les phénomènes connexes tels que la superfluidité, la spinoptronique, le laser à polaritons à température ambiante, sont étudiés. Un autre sujet de recherche est la manipulation de la lumière dans les cristaux et les métamatériaux photoniques.

L'activité Nanophotonique et Nanostructures de l'Institut Pascal est divisée en trois groupes de recherche qui collaborent étroitement :

• Optoélectronique Quantique et Nanophotonique
• Spectroscopie optique des solides
• Electromagnétisme et Nanophotonique

Cette entité résulte d'une alliance entre la physique de l'état solide, l'électromagnétisme optique et l'expérimentation en spectroscopie optique. Nous étudions la manipulation de la lumière et son contrôle, à l'aide de nanostructures. Les phénomènes fondamentaux sont étudiés tels que la condensation de Bose-Einstein des excitons-polaritons, la superfluidité, la spinoptronique. Ces phénomènes se produisent dans une microcavité opérant en régime de couplage fort. Les structures à base de GaN et ZnO sont au coeur des études expérimentales :  elles permettent d'observer les effets mentionnés ci-dessus à température ambiante. Un autre projet étudie la manipulation de la lumière en utilisant des cristaux ou des métamatériaux photoniques. Nous collaborons avec de nombreux groupes expérimentaux et théoriques en France et dans le monde (30 partenaires) et sommes reconnus internationalement. Nous sommes impliqués dans de nombreux projets français (deux LabEx, plusieurs ANR) et des projets européens, dont une coordination de projet.

Production du groupe N2 sur le dernier plan de contractualisation (2010-2015) : 150 articles internationaux, 29 invitations internationales.

Audience cumulée depuis la création du groupe (ex-LASMEA, puis Institut Pascal) : plus de 7000 citations sur les articles du groupe. 26 articles cités plus de 100 fois, 74 plus de 50 fois (source : Web of Science).

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