Effective properties of amorphous metamaterials

We experimentally and numerically study the propagation of light through amorphous metamaterials. For this purpose we introduce a precisely controllable degree of positional disorder into a perfectly periodic system, transforming it to a partially disordered and ultimately an amorphous metamaterial. The observable spectral features occurring upon this transition and the impact of coherent interactions among neighboring unit cells are revealed. Backed by numerical simulations, the effective properties of the metamaterials are retrieved, most notably for the amorphous one. The most important finding with respect to negative index materials is that their magnetic properties are not affected by an arbitrarily high degree of disorder. This work enables the quantitative evaluation of effective properties of amorphous metamaterials fabricated by bottom-up approaches.