Scientific Programme
Metamaterials
"Why light bends the wrong way"
"Why things don't fall down"
Abstract BookMetamaterials have physical properties (optical and/or mechanical) determined by their structure instead of their bulk chemical constituents. They can be natural (plant stem – made of soft material, cytoskeleton, biopolymers) but are mostly artificial. The recent realisation of metamaterials bending light the wrong way (with negative index of refraction) and the extraordinary physical properties of these materials (flat, perfect lenses free from resolution restrictions and, possibly, invisibility screen) have generated an extraordinary interest. Similarly, the photon sieve, a metallic plate with a regular array of holes, is much more than a super transparent material but a device storing and re-emitting electromagnetic energy. The concept of metamaterial (fold, arches or buttresses) has been used for centuries to redirect stresses in bridges or gothic cathedrals (“why things don’t fall down”), to prevent the catastrophic growth of fractures or in the design of weaved tissues (clinging or hanging fabrics). Thus, the assembly of elements in a particular structure responsible for one or several physical properties has been developed by Darwinian evolution or by scientific endeavour. We will try to understand how and why.
Introduction
Opening of the 9th European Summer University
U. Goerlach, IPHC and UdS Strasbourg
talk
Lectures
1) Negative refraction (“Why light bends the wrong way”)
A composite material with resonances of the electric and magnetic fields in the same frequency range has a negative refractive index. It bends the light the wrong way, and constitutes a perfect lens that is flat with a resolution beyond the diffraction limit.
Course: Aloyse Degiron, Orsay
talk
2) Photon sieve
Light incident on a metallic plate transpierced with a lattice of nano-sized holes is reemitted on the other side with extraordinary efficiency. The plate is much more “transparent” than the total geometric cross section of the holes. It is the lattice of holes that makes the material super transparent.
Course: Cyriaque Genet, Strasbourg
3) Photonic Crystals and Photonic Metamaterials (Visit to the Karlsruhe Institute of Technology, Institute of Applied Physics)
Both photonic crystals and metamaterials can be viewed as artificial materials with tailored optical properties. In addition to negative refractive indices, photonic metamaterials also allow for giant chiral effects, enhanced nonlinear optics, and for shaping optical space via transformation optics. Photonic crystals enable photonic band gaps and a tailored "electromagnetic vacuum". Theory (Kurt Busch) and experiment (Martin Wegener) will be covered. The visit to Karlsruhe also includes laboratory visits.
Course: Kurt Busch and Martin Wegener, Karlsruhe; Visit of laboratory: M. Wegener
talk
4) Structural metamaterials (“Why things don’t fall down”)
The manifold of available materials is not only an asset, it is also a challenge. This has led in recent years to the development of systematic material selection methods providing guidelines to select, for a given set of requirements, the best possible solutions. The first part of the course will deal with this manifold and with the material selection methods and software.
In spite of this huge manifold, the requirements are often contradictory, and for some of these contradictions there is no “single material solution”. This has led to the development of hybrid materials, or “metamaterials” where material associations, geometry and topology provide new strategies to “expand the material world”. The second part of the course will deal with these new developments in material science.
Course: Yves Bréchet, Grenoble
5) Soft metamaterials
Examples of soft metamaterials: Entropic elasticity, polymer melts, Casimir effect in vacuum and in polymers.
Course: Sergei Obukhov, Gainesville, FL
6) Cytoskeleton and motion of living cells
Stress-strain and rheology of living cells through the nonlinear elasticity of a network of semi flexible, sliding filaments
Course: Ben Fabry, Erlangen
7) Elasticity of textile fabrics and yarns
Why our clothes are made of textile materials? Answer to this interesting question needs to understand the specific structure of these materials. Indeed, fibres are assembled together to form yarns which are interlaced to give fabrics. Their mechanical properties strongly depend on the structure at different scale levels. And, while it is easy to define Young’s modulus and Poisson ratio for homogeneous materials, these quantities are somewhat questionable in the textile area. Specialists of spinning (A. Sinoimeri), weaving (J. Y. Dréan) and knitting (M. A. Bueno) will explore these problems in order to explain the 3D body clothing (C. Jung). Small experiments will be proposed.
Artan Sinoimeri, Jean-Yves Dréan, Marie-Ange Bueno, Corinne Jung,
Coordinator: Dominique Dupuis, ENSISA-UHA, Mulhouse
8) Auxetic Metamaterials (materials with a negative Poisson's ratio)
A few materials and structures get fatter when stretched (i.e. exhibit a negative Poisson's ratio). Despite being rare, it is a desirable property since such materials offer an increased resistance to indentation, enhanced vibration absorption properties and an ability to curve like a dome under stress (instead of a saddle). We will present examples (natural and artificial), models and the mechanisms responsible for auxetic behaviour
Course: Joseph N. Grima, University of Malta
talk
Evening Lecture
Evening Lecture in common with the French Physical Society (SFP):
Negative Refraction & the Perfect Lens
Sir John Pendry, Imperial College
talk
Prelude
An introduction to several essential concepts, (origin of the refractive index, critical size for nucleation or fracture, stress and strain, etc.) will be given by one or several members of the local scientific committee.
Tutorial - Polymers
Entropic elasticity. Design of a worm.
Excluded volume exclu and phase transition
N. Rivier, IPCMS Strasbourg
talk part 1 - talk part 2
Round table discussions: (to be confirmed)
- What is the smallest size of an object which can still be classified as a metamaterial?
- How many atoms will form a critical cluster for nucleation?
- Invisibility: is it science-fiction or can it become reality?
- Any similarities between electromagnetic and structural metamaterials?
Poster session
We offer to our students the possibility to present their research work or their university in an informal poster session at the beginning of the Summer Campus. The goal is to ease the process of first contacts; the posters will be displayed during the entire week.
Documentation:
The documents related to all lectures will be placed on our web-site as soon as they are available and video streams of all lectures will be distributed on DVD after the end of the Summer Campus.
The European Aspect
A guided visit to the architecturally and functionally impressive buildings of the Council of Europe combined with a presentation and a discussion with a representative of the Council will provide background information about the European Institutions in Strasbourg.
Social and Cultural Programme
Alsace is a region with rich cultural and historical legacy and its position along the border between France and Germany has made it an important economical focal point. Some excursions in Strasbourg and a trip to the countrysid