Open Access
EPJ Applied Metamaterials
Volume 1, 2014
Article Number 8
Number of page(s) 10
Published online 06 April 2015

© Y. He and G.V. Eleftheriades, Published by EDP Sciences, 2015

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.