arXiv subjects

David Figueiredo

Publications and source records attributed to David Figueiredo.

3 recordsLinked to original sources

arXiv2018

Optical concentrator from a hyperbolic liquid crystal metamaterial

We examine the optical properties of two different configurations of a cylindrical device made from a hyperbolic metamaterial with optical axis defined by circular and radial director fields. The hyperbolic metamaterial is an uniaxial anisotropic medium for which the ratio between ordinary and extraordinary permittivities is negative, leading to a particular effective geometry with two timelike coordinates in the metric (Kleinian signature). By using differential geometry tools we are able to perform a comparison between a simple geometrical optics treatment and the wave formalism that shows the concentration of light along the cylinder axis for the case of the circular field configuration, whatever the injection conditions are.

physics.optics↗

arXiv2017

Cosmology in the laboratory: an analogy between hyperbolic metamaterials and the Milne universe

This article shows that the compactified Milne universe geometry, a toy model for the big crunch/big bang transition, can be realized in hyperbolic metamaterials, a new class of nanoengineered systems which have recently found its way as an experimental playground for cosmological ideas. On one side, Klein-Gordon particles, as well as tachyons, are used as probes of the Milne geometry. On the other side, the propagation of light in two versions of a liquid crystal-based metamaterial provides the analogy. It is shown that ray and wave optics in the metamaterial mimic, respectively, the classical trajectories and wave function propagation, of the Milne probes, leading to the exciting perspective of realizing experimental tests of particle tunneling through the cosmic singularity, for instance.

gr-qc↗

arXiv2016

Modeling Kleinian cosmology with electronic metamaterials

This paper deals with the propagation of Klein-Gordon particles in flat background spacetime exhibiting discontinuous metric changes from a Lorentzian signature (-,+,+,+) to a Kleinian signature (-,+,+,-). A formal analogy with the propagation of electrons at a junction between an anisotropic semiconductor and an electronic metamaterial is presented. From that analogy, we study the dynamics of these particles falling onto planar boundary interfaces between these two families of media and show a mirror-like behavior for the particle flux. Finally, the case of a double junction of finite thickness is examined and the possibility of tunneling through it is discussed. A physical link between the metamaterial and the Kleinian slabs is found by calculating the time of flight of the respective traversing particles.

gr-qc↗