Ricardo Marques

Babinet's principle is widely applied in optics and has been useful for designing metasurfaces with dual behavior. Although this principle can be rigorously demonstrated for infinitely thin perfect conducting screens, it is not exact for any real screen. In fact, metals used in plasmonic metasurfaces are far from good conductors, and the thickness of samples is not negligible in comparison with the typical size of the patterned structure. In this paper, we propose an extension of Babinet's principle valid for plasmonic metasurfaces by redefining the concept of complementary screens and finding impedance relations between such screens that ultimately leads to a simple relation between the transmission matrices of two complementary plasmonic metasurfaces. The theory is valid under the assumptions of the electroquasistatic approximation and plane waves in the far field. It may find applications in the design of optical plasmonic metasurfaces, nanocircuits, and nanoantennas.

It has been previously demonstrated that the resonant frequency of the Split Ring Resonator (SRR) reaches a saturation value when its size is continuously scaled down, and at the same time, the resonance is attenuated. Now, it is demonstrated that similar saturation and attenuation phenomena happens to its complementary screen, which is commonly called a Complementary SRR (CSRR). It was found that the saturation frequency of the CSRR is near the saturation frequency of the SRR with equal geometrical dimensions. It is possible to control their saturation levels by tuning the geometry of the resonators. This work is relevant for the design of quasi-optical metamaterials based on one or both kinds of structures (i.e., SRRs and CSRRs) at once, especially when they both are required to resonate at the same frequency.

This paper analyzes the impact of the creation of a continuous network of segregated cycle paths on local economy and on the touristic image of cities, through the case study of the city of Seville by developing a methodology that could be applied to the analysis of other similar experiences. The implementation of a network of bike tracks in the city from 2007 onwards led to the revitalization of a sector, quite marginal until that date, turning it into a dynamic and growing sector in an environment of economic crisis, with high job creation rates per euro billed, something quite beneficial in a city with high rates of unemployment. The impact of the creation of the mentioned network of cycle paths in the touristic image of the city, something very important given the relevance of the tourism in its economy, is apparent from the inclusion of the aforementioned infrastructure in the main international tourist guides of the city. The microanalysis of the opinions of the visitors, users of said infrastructure, evidences a positive valuation, and its high multiplier power as an argument for recommending Seville as a tourist destination in their immediate social environments. However, some deficiencies that should still be corrected are detected, such as conservation problems, or the low level of knowledge of such infrastructure at the international level.

>From 2006 to 2011 Sevilla experienced a rapid growth in urban cycling, from a negligible participation in the modal split up to 9% of the total...

A generalized transverse waveguide analysis for Extraordinary Transmission (ET) and Fishnet Metamaterials (FMs) in realistic metallic screens has recently been published by the authors [1]. The model is valid for lossy metallic screens thanks to the Surface Impedance (SI) approximation (e.g. [2]). A standard scattering matrixes formalism makes the model applicable to stacked screens with possible dielectric boards. A number of reported phenomena [3, 4] related to screens with a periodic array of slits or holes are reproduced efficiently with the presented analysis.

This work presents a method to calculate the noise correlation between magnetic resonance imaging coils loaded with metamaterial lenses and in the presence of a conducting phantom resembling human tissue. The method is validated by the comparison with experimental results. With this method it is studied the ability of magneto inductive lenses to decrease the noise correlation between coils in the array and thus to increase the signal-to-noise ratio.