Optical metamaterials: Possibilities and limitationsM. Kafesaki, R. Penciu, Th. Koschny, N. H. Shen, D. Guney, J. Zhou, E. N. Economou and C. M. SoukoulisIESC Proceedings, (2010) 01011DOI: https://doi.org/10.1051/iesc/2010mpcm01011