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Advances in OptoElectronics
Volume 2012, Article ID 439147, 9 pages
Research Article

Field Enhancement in a Grounded Dielectric Slab by Using a Single Superstrate Layer

1Department of Radio Science and Engineering, School of Electrical Engineering, Aalto University, Otakaari 5A Street, 02150 Espoo, Finland
2Department of Informatics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece

Received 19 June 2012; Revised 22 September 2012; Accepted 24 September 2012

Academic Editor: Natalia M. Litchinitser

Copyright © 2012 Constantinos A. Valagiannopoulos and Nikolaos L. Tsitsas. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The addition of a dielectric layer on a slab configuration is frequently utilized in various electromagnetic devices in order to give them certain desired operational characteristics. In this work, we consider a grounded dielectric film-slab, which is externally excited by a normally-incident Gaussian beam. On top of the film-slab, we use an additional suitably selected single isotropic superstrate layer in order to increase the field concentration inside the slab and hence achieve optimal power transfer from the external source to the internal region. We define a quantity of interest, called “enhancement factor,” expressing the increase of the field concentration in the film-slab when the superstrate is present compared to the case that it is absent. It is shown that large enhancement factor values may be achieved by choosing properly the permittivity, the permeability, and the thickness of the superstrate. In particular, it is demonstrated that the field in the film-slab is significantly enhanced when the slab is composed by an ϵ-near-zero (ENZ) or low-index metamaterial.