Mathias FINK - Institut d'études scientifiques de Cargèse (IESC)

disordered media leads to substantial changes in the photonic properties, compare to that of bulk
materials. Changes in the local density of optical states (LDOS) influence spontaneous emission as
well as absorption of light (weak coupling regime or Purcell effect). Disorder also influences the
intrinsic spatial coherence that can be described by the concept of cross density of states (CDOS). A
reduction of the intrinsic spatial coherence can reveal the spatial localization of modes in a
complex system. The strong coupling regime can even be reached between a resonant scatterer (or
emitter) and an Anderson localized mode. In the lecture we will focus on the basic concepts used to
describe the different interaction regimes, and illustrate the main trends based on numerical
simulations and experiments. We will also discuss some analogies between different kind of
measurements that are actually driven by the same features of the underlying structure of the optical
eigenmodes.
Pr. Didier Felbacq
Universality and scaling in topological metamaterials
The presentation will deal with electromagnetic wave propagation in a model metamaterial made of
dielectric rods. The scatterers are such that they present a double resonance (magnetic and electric)
in such a way that conduction bands are opened. A low frequency analysis will show that the
behavior of the system can be described by resonant (dispersive) electromagnetic parameters ε and
μ. The bands have universal features with respect to symmetry and scaling, that will be explored
numerically. The link with photonic topological insulators will be discussed as well as the transition
to Anderson localization.
Dr. Sylvain Gigan
Matricial approach to optical wavefront engineering
The randomness of the refractive index and/or the position of the scatterers blur the images in
biological tissues. OCT by selecting singly backscattered photons is a first approach that allows
overcoming this problem. Even with incoherent sources the OCT signal exhibits a speckle
distribution. Despite of the speckle in the images the Full Field OCT (FFOCT) approach that we
have developed allows to reveal the tissue morphology at the micron scale and starts to be a
valuable tool in intra operative surgery. Sometimes the morphology is not enough to characterize
the tissue, so we will examine the basic nature of the signal and what kind of supplementary
information can be extracted from the OCT data such as local refractive index, density of scatterers
and elasticity map. Finally (because we are in Cargese !) I will shows how FFOCT is used to count
and characterize, through their Brownian trajectories, viruses in see water.
Dr. Stefan Enoch
Scaling up the holes : Towards Seismic metamaterials
It has been recently suggested that structured media can bend light trajectories the wrong way,
making a flat convergent superlens, or even detour light around an objsect, making an invisibility
cloak. Such electromagnetic metamaterials introduced by Sir John Pendry during the last decade
have counterparts in acoustics. In this talk, I will focus my attention on certain type of surface
waves : flexural (Lamb) waves propagating within thin elastic metamaterial plates which have been
experimentally studied this year by research groups in Wegener in Karlsruhe, Vandenberghe in
Marseille, with applications thought in cloaking, and Sebbah’s group in Paris, where the dynamics
of a flat lens for Lamb waves has been unveiled. Interestingly, control of flexural waves opens a
route towards seismic metamaterials. First experiments performed by multinational company
Menard this year near the French cities of Grenoble and Lyon demonstrate that one can shield or
even focus a seismic wave of magnitude 4 on the Richter scale through an array of meter sized