Iñigo Liberal
Universidad Pública de Navarra
Iñigo Liberal got his PhD from the Public University of Navarra, September 2013, where his research was focused on antenna theory and physical bounds on electromangetic scattering. After completing his doctorate, he took a postdoctoral position at the University Pennsylvania, where he work on geometry-invariant effects associated to light-matter interactions in zero-index media. Since March 17, he is at the Public University of Navarre as the recipient of a Juan de la Cierva Incorporation Fellowship. His research interests include antenna theory, metamaterials and quantum optics.
Effective medium theories (EMTs) are a powerful tool that enable the description of complex electromagnetic systems in terms of simple effective parameters (e.g., effective permittivity, permeabilily, chirality…). In fact,... [ view full abstract ]
Effective medium theories (EMTs) are a powerful tool that enable the description of complex electromagnetic systems in terms of simple effective parameters (e.g., effective permittivity, permeabilily, chirality…). In fact, homogenizations techniques associated with EMTs lie at the core of metamaterial science. Indeed, they describe the emergence of exotic properties (e.g., artificial magnetism, negative refraction…) as a consequence of the structure of their constitutive particles. However, EMTs suffer from strict limitations on their range of applicability. Typically, they are only valid for a sufficiently large number of particles, which must be small in size, and arranged with high density.
Thus, a two-dimensional (2D) structure such as that depicted in Fig.1a, would usually have no hope to be described via EMTs. However, the situation is exceptional if the refractive index of the host approaches zero. As we demonstrated in a recent work [Liberal et al. Science 355(6329), 1058-1063 (2017)], the limitations of EMTs can be circumvented in 2D epsilon-near-zero (ENZ) media. In this manner, an arbitrarily shaped body made of zero-index medium containing an arbitrary number of particles, and of any size, can still be described with effective material parameters. Furthermore, each particle contributes to the effective constitutive parameters in an additive, noninteracting, manner; an effect we named as ‘photonic doping’.
This methodology offers new possibilities in engineering light-matter interactions. For example, it allows for synthesizing exotic materials such as epsilon-and-mu-near-zero media and perfect-magnetic-conductors (see Figs. 1). It also facilitates the control of a large body with a single, arbitrarily located, particle, and this effect persists even when realistic material parameters are taken into consideration (see Fig. 2). Pathological effects, different from those in conventional EMTs, also appear when the filling factor of the particles approaches one.
In our presentation, we will discuss the theory and underlying principles of this concept. We will also cover some proposals for practical implementations in the mid-IR based on silicon carbide (SiC), and we will review a number of potential applications, including flexible and reconfigurable metasurfaces, nonlinear optics, as well as thermal and nonclassical light sources.
