Abstract

For most MMs fabricated by top down methods the strategy to introduce effective material parameters turned out to be inadequate. The strictly periodic arrangement of meta-atoms with a mesoscopic size leads to a nonlocal response that in fact is identical to strong spatial dispersion. Evidently, this is not a satisfying situation since the proper theoretical description in terms of effective properties is very desirable if MMs shall serve as building blocks of functional devices. One possible strategy to overcome these difficulties is to use amorphous MMs. There meta-atoms are randomly arranged and spatial dispersion, at least that caused by the periodic arrangement, is suppressed. Effective properties can be assigned to the bulk material while considering only the electric and magnetic dipole contributions to the scattered field from individual meta-atoms. However, spatial dispersion may arise from higher order multipoles. Thus the meta-atoms have to be probed for the existence of these multipoles. For a perfect amorphous arrangement and orientation of all meta-atoms, genuine isotropic MMs seem to be in reach. Therefore the aim of this contribution is the exploration of strategies for assigning effective properties to amorphous MMs.

© 2012 Optical Society of America