Direct dark mode excitation by symmetry matching of a single-particle based metasurface

This paper makes evidence for direct dark mode excitation mechanism in a metasurface structure. The dark mode excitation mechanism is entirely determined by structures' symmetry and does not depend on near-field coupling between elements. In our examples, we consider single element based metasurface composed of two V antennas connected in an anti-symmetric arrangement. Both experimental and modeling results show an efficient excitation of magnetic dipolar mode in such structures. The direct dark mode excitation mechanism provides a design that is more robust with respect to technology imperfections. The considered approach opens promising perspectives for new type of nanostructure designs and greatly relaxes fabrication constraints for the optical domain.Comment: 21 pages, 5 figure

Absorbants à métamatériaux (étude théorique et expérimentale)

Les matériaux absorbants électromagnétiques, ou Radar Absorbing Materials (RAM), ont été créés à la fois aux USA et en Allemagne lors de la seconde guerre mondiale. Les applications des absorbants appartiennent principalement aux domaines de la Compatibilité ElectroMagnétique (CEM) et de la discrétion radar. Ces absorbants sont lourds et encombrants. Au travers de cette thèse, nous cherchons à développer une solution pour pallier à ces inconvénients grâce aux absorbants à métamatériaux. Les métamatériaux sont des composites artificiels présentant des propriétés électromagnétiques que l'on ne retrouve pas dans la nature. En utilisant ce type de matériaux, nous pouvons obtenir des absorbants ultras fins, et par l'optimisation et la conception couvrir des bandes larges en fréquence. Nous proposons donc plusieurs formes basiques d'absorbant à métamatériaux. De ces formes, nous présentons un modèle théorique et développons les techniques pour définir leur fréquence de fonctionnement et les paramètres nécessaires pour obtenir une absorption totale. Puis nous étudions plus en détail nos différents prototypes à travers des simulations et des mesures. Nous étudions aussi le couplage des absorbants à métamatériaux avec des absorbants traditionnels pour créer un type d'absorbant inédit.Electromagnetic absorbing materials, or "Radar Absorbing Materials" (RAM), were created in the U.S. and Germany at the same time during the Second World War. Applications of absorbers are mainly in the field of ElectroMagnetic Compatibility (EMC) and radar stealth. These absorbers are heavy and bulky. In this thesis, we seek to develop a solution to overcome these drawbacks using metamaterial absorbers. Metamaterials are artificial composites with electromagnetic properties that are not found in nature. By using this type of material, we can obtain ultra-thin absorbers over a wide band of frequency by optimizing the design. We introduce several basic forms of metamaterial absorbers. From these geometries, we present a theoretical model and we develop techniques to define their operating frequency and parameters required to achieve total absorption. Then we study in detail our various prototypes with simulations and measurements. We also study the coupling of metamaterial absorbers with traditional ones to create a new type of absorber.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Ultra-compact on-chip metaline-based 1.3/1.6 μm wavelength demultiplexer

International audienceIn this article, we report an experimental demonstration of enabling technology exploiting resonant properties of plasmonic nanoparticles, for the realization of wavelength sensitive ultra-minituarized (4×4 µm) optical metadevices. To this end the example of a 1.3/1.6 µm wavelength demultiplexer is considered. Its technological implementation is based on the integration of gold cut wire based metalines on the top of a silicon on insulator waveguide. The plasmonic metalines modify locally the effective index of the Si waveguide and thus allow for the implementation of wavelength dependent optical pathways. The 1.3/1.6µm wavelength separation with extinction ratio between two demultiplexer's channels reaching up to 20dB is experimentally demonstrated. The considered approach, which can be readily adapted to other planar lightwave circuits platforms and nanoresonators of different types of materials, is suited for the implementation of a generic family of wavelength sensitive guided wave optical metadevices. http://dx

High-Q Fano resonances via direct excitation of an antisymmetric dark mode

International audienc

Directive metamaterial-based subwavelength resonant cavity antennas – Applications for beam steering

International audienceThis article presents the use of composite resonant metamaterials for the design of highly directive subwavelength cavity antennas. These metamaterials, composed of planar metallic patterns periodically organized on dielectric substrates, exhibit frequency dispersive phase characteristics. Different models of metamaterial-based surfaces (metasurfaces), introducing a zero degree reflection phase shift to incident waves, are firstly studied where the bandwidth and operation frequency are predicted. These surfaces are then applied in a resonant Fabry-Perot type cavity and a ray optics analysis is used to design different models of ultra-compact high-gain microstrip printed antennas. Another surface presenting a variable reflection phase by the use of a non-periodic metamaterial-based metallic strips array is designed for a passive low-profile steering beam antenna application. Finally, the incorporation of active electronic components on the metasurfaces, allowing an electronic control of the phase responses, is applied to an operation frequency reconfigurable cavity and a beam steering cavity. All these cavity antennas operate on subwavelength modes, the smallest cavity thickness being of the order of lambda/60. To cite this article: A. Outir et al., C R. Physique 10 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved

Applications de matériaux à bandes interdites photoniques et de métamatériaux en télécommunications

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF