Angular resolved effective optical properties of a Swiss cross metamaterial

We both experimentally and theoretically study the effective optical properties of a Swiss cross metamaterial at oblique incidence and reveal their angular dependence. Almost perfect agreement between measured and calculated data is achieved. We show that the spectral and angular domains of negative refraction as well as its strength depend strongly on the light's propagation direction and polarization state. Our results clearly indicate that a description of a Swiss cross metamaterial in terms of effective material parameters is impossible. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3238554]