Light propagation in all-dielectric rod-type metamaterials is studied theoretically. The electric and magnetic dipole moments of the rods are derived analytically in the long-wavelength limit. The effective permittivity and permeability of a square lattice of rods are calculated by homogenizing the corresponding array of dipoles. The role of dipole resonances in the optical properties of the rod array is interpreted. This structure is found to exhibit a true left-handed behavior, confirming previous experiments [L. Peng et al., Phys. Rev. Lett. 98, 157403 (2007)]. A scaling analysis shows that this effect holds at optical frequencies and can be obtained by using rods made, for example, of silicon.

The direction of propagation followed by a monochromatic beam in a periodic structure is generally deduced from the isofrequency diagram, which is related to the group velocity. However, the group velocity is the derivative of omega with respect to the wavenumber, while the behavior of the beam should depend on omega only. In the subwavelength regime, a method for choosing the relevant branch of the isofrequency diagram and relying on the behavior of the system at omega only is described. (C)d 2008 Optical Society of America.

Wave propagation in thin nanostructured films in the low frequency regime is studied. By means of a two-scale analysis, it is shown that the medium can be homogenized, i.e. described by effective electromagnetic parameters. The effective permeability and permittivity are obtained by solving a set of partial differential equations. A numerical aproach based on the Fourier Modal Method is proposed in order to solve these equations.

We demonstrate an isotropic phase matching condition achieved in nonlinear 2D PhCs that suppresses the incident angle constraint [1]. In addition, we show a backward SH localization effect by combining this unusual all-angle phase matching and left-handed PhC properties. The SH emission is confined in a small area of dimension close to the pump wavelength without the introduction of defect lattices. An analytical model is proposed in order to explain this parametric localization mechanism.

The metamaterials exhibiting negative permittivity and permeability that have been under numerical and experimental study recently generally operate at frequencies between the homogeneous and heterogeneous regimes, a region characterized by the phenomenon of spatial dispersion. However, since many interesting applications such as the superlens rely on nondispersive homogeneous behavior, one needs a means to diagnose spatial dispersion efficiently as well as to explore in more detail the physics of dispersive media. In this work, we put forward and illustrate the notion of an inhomogeneous effective medium model. We use it to explore the spatial dispersion in negative-index composites, and we show that it is an ideal tool for studying the behavior of composite metamaterials in the intermediate-frequency region where homo- geneous effective medium models become spatially dispersive or nonlocal.

On étudie des ensembles de diffuseurs à haut facteur de qualité. La présence de modes internes entraîne l'ouverture de canaux pour la transmission de la lumière.