Spectral super-resolution in metamaterial composites

TL;DR

This paper explores how the optical properties of metamaterial composites with sharp-corner inclusions can be used to deduce their shape through spectral analysis, supported by analytic and numerical results.

Contribution

It introduces a method to determine inclusion shape in metamaterials via spectral measurements, supported by analytic and numerical evidence.

Findings

Spectral component limits are independent of inclusion area fraction.

Effective permittivity function shows a continuous spectral component.

Results are consistent across different array configurations.

Abstract

We investigate the optical properties of periodic composites containing metamaterial inclusions in a normal material matrix. We consider the case where these inclusions have sharp corners, and following Hetherington and Thorpe, use analytic results to argue that it is then possible to deduce the shape of the corner (its included angle) by measurements of the absorptance of such composites when the scale size of the inclusions and period cell is much finer than the wavelength. These analytic arguments are supported by highly accurate numerical results for the effective permittivity function of such composites as a function of the permittivity ratio of inclusions to matrix. The results show that this function has a continuous spectral component with limits independent of the area fraction of inclusions, and with the same limits for both square and staggered square arrays.