Colloquium: Light scattering by particle and hole arrays

This colloquium analyzes the interaction of light with two-dimensional periodic arrays of particles and holes. The enhanced optical transmission observed in the latter and the presence of surface modes in patterned metal surfaces are thoroughly discussed. A review of the most significant discoveries in this area is presented first. A simple tutorial model is then formulated to capture the essential physics involved in these phenomena, while allowing analytical derivations that provide deeper insight. Comparison with more elaborated calculations is offered as well. Finally, hole arrays in plasmon-supporting metals are compared to perforated perfect conductors, thus assessing the role of plasmons in these types of structures through analytical considerations.Comment: 19 figure

Polarization state of the optical near-field

The polarization state of the optical electromagnetic field lying several nanometers above complex dielectric structures reveals the intricate light-matter interaction that occurs in this near-field zone. This information can only be extracted from an analysis of the polarization state of the detected light in the near-field. These polarization states can be calculated by different numerical methods well-suited to near--field optics. In this paper, we apply two different techniques (Localized Green Function Method and Differential Theory of Gratings) to separate each polarisation component associated with both electric and magnetic optical near-fields produced by nanometer sized objects. The analysis is carried out in two stages: in the first stage, we use a simple dipolar model to achieve insight into the physical origin of the near-field polarization state. In the second stage, we calculate accurate numerical field maps, simulating experimental near-field light detection, to supplement the data produced by analytical models. We conclude this study by demonstrating the role played by the near-field polarization in the formation of the local density of states.Comment: 9 pages, 11 figures, accepted for publication in Phys. Rev.

Atomic diffraction from nanostructured optical potentials

We develop a versatile theoretical approach to the study of cold-atom diffractive scattering from light-field gratings by combining calculations of the optical near-field, generated by evanescent waves close to the surface of periodic nanostructured arrays, together with advanced atom wavepacket propagation on this optical potential.Comment: 8 figures, 10 pages, submitted to Phys. Rev.

Extreme stiffness hyperbolic elastic metamaterial for total transmission subwavelength imaging

Subwavelength imaging by metamaterials and extended work to pursue total transmission has been successfully demonstrated with electromagnetic and acoustic waves very recently. However, no elastic counterpart has been reported because earlier attempts suffer from considerable loss. Here, for the first time, we realize an elastic hyperbolic metamaterial lens and experimentally show total transmission subwavelength imaging with measured wave field inside the metamaterial lens. The main idea is to compensate for the decreased impedance in the perforated elastic metamaterial by utilizing extreme stiffness, which has not been independently actualized in a continuum elastic medium so far. The fabricated elastic lens is capable of directly transferring subwavelength information from the input to the output boundary. In the experiment, this intriguing phenomenon is confirmed by scanning the elastic structures inside the lens with laser scanning vibrometer. The proposed elastic metamaterial lens will bring forth significant guidelines for ultrasonic imaging techniquesope

Estación depuradora de aguas en Ginebra – Suiza

The sanitation policy wisely adopted by the ruling bodies of the Canton has followed two fundamental criteria which have led to original results: to create plants which are structurally simple and evolutionary, with a look of the future about them; to integrate as far as possible the disposal and treatment of all urban wastes, whether solid, liquid, muddy, industrial or domestic. This sewage plant has been designed, in its first phase, for 400,000 inhabitants, but with the possibility of being extended in stages of 50,000 people, while keeping its functional aspect as well as aesthetic appearance. The most modern techniques have been used in all the present and future plants, thus allowing their sizes to be reduced and the buying of costly and scarce land avoided.<br><br>La política de saneamiento adoptada acertadamente por los Organismos rectores del Cantón ha seguido dos criterios fundamentales que han conducido a soluciones originales: crear instalaciones de estructuras abiertas y evolutivas, de cara al futuro; integrar, en lo posible, la evacuación y el tratamiento de todos los desechos urbanos sólidos, liquides, fangosos, industriales y domésticos. La estación depuradora se ha dimensionado, en primera fase, para 400.000 habitantes, pero con posibilidad de ser ampliada por etapas de 50.000 personas, cuidando el aspecto funcional y también el estético. Se han previsto todas las instalaciones actuales y futuras con las técnicas más avanzadas, permitiendo así reducir las dimensiones de las instalaciones y evitar la compra de terrenos costosos y escasos

A Poincaré's approach for plasmonics: the plasmon localization

International audienceA Poincaré's approach is employed to characterize the excitation of a plasmon, which in essence corresponds to a zero of a complex S‐matrix. Throughout this work we study the plasmonic behaviour of gold, as this metal not only is frequently used in experimental arrays, but also requires an accurate dispersion model to properly excite plasmons. We investigate the plasmonic behaviour of gold nanogratings by means of Born's approximation and the Finite‐Elements Method. Also, a method based on the Poincaré's approach is proposed to optimize this kind of structures