Propagation of light through layered metamaterials consisting of a metal-dielectric stack may be described as linear spatial filtering. We present the modelling and optimization strategy for engineering such metamaterials, as well as the measurement results of spatial filters consisting of titanium oxide and silver layers evaporated with PVD. Depending on the point spread function, the metamaterial can be applied for subdiffraction spatial filtering or for classical spatial filtering operations. We optimize the metamaterial with respect to the shape of the complex amplitude transfer function, the average transmission coefficient and to average reflections. The shape of the point spread function can only be tailored in a limited degree, due to the limited number of the degrees of freedom contained in the structure, and only in one, planarly or radially oriented dimension. The metamaterial optimised for high-pass filtering consists of several substructures, each of which is an individual cavity, and is optimized by tuning the resonance order of these cavities. In this way we obtain a high transmission for a broad range of spatial frequencies. This metamaterial can be applied to modify the contrast of the object or to introduce a phase-contrast. It may be used for far-field imaging. As an example, we propose to apply it as a novel phase-step visualization photonic element.

Date Published: 6 May 2013
PDF: 7 pages
Proc. SPIE 8771, Metamaterials VIII, 87710J (6 May 2013); doi: 10.1117/12.2019813

Published in SPIE Proceedings Vol. 8771:
Metamaterials VIII
Vladimir Kuzmiak; Peter Markos; Tomasz Szoplik, Editor(s)