Subwavelength internal imaging by means of the wire medium

TL;DR

This paper demonstrates that a thin wire medium slab can amplify evanescent waves and enable subwavelength internal imaging, revealing details smaller than the wavelength that are not visible at the surface.

Contribution

It provides the first experimental evidence of evanescent wave amplification inside a wire medium slab for subwavelength imaging, analyzed with advanced simulation methods.

Findings

Evanescent wave amplification observed inside the slab.

Subwavelength details detectable within the slab.

Resolution of approximately one-tenth of a wavelength.

Abstract

Evanescent wave amplification is observed, for the first time to our knowledge, inside a half-wavelength-thick wire medium slab used for subwavelength imaging. The wire medium is analyzed using both a spatially dispersive finite-difference time-domain (FDTD) method and a full-wave commercial electromagnetic simulator CST Microwave Studio. In this work we demonstrate that subwavelength details of a source placed at a distance of one-tenth of a wavelength from a wire medium slab can be detected inside the slab with a resolution of approximately one-tenth of a wavelength in spite of the fact that they cannot be resolved at the front interface of the device, due to the rapid decay of evanescent spatial harmonics in free space.