Far field subwavelength imaging and focusing using a wire medium based resonant metalens

TL;DR

This paper demonstrates a resonant metalens made of wire medium that achieves subwavelength imaging and focusing in the far field, with experimental resolution of λ/80, highlighting the potential and limitations of such lenses.

Contribution

It introduces a new resonant metalens design using wire medium for far-field subwavelength imaging and demonstrates experimental super-resolution focusing and imaging.

Findings

Achieved subwavelength focusing with λ/25 width.

Reconstructed images with resolution of λ/80.

Identified losses as main limitations.

Abstract

This is the second article in a series of two dealing with the concept of "resonant metalens" we introduced recently [Phys. Rev. Lett. 104, 203901 (2010)]. It is a new type of lens capable of coding in time and radiating efficiently in the far field region sub-diffraction information of an object. A proof of concept of such a lens is performed in the microwave range, using a medium made out of a square lattice of parallel conducting wires with finite length. We investigate a sub-wavelength focusing scheme with time reversal and demonstrate experimentally spots with focal widths of {\lambda}/25. Through a cross-correlation based imaging procedure we show an image reconstruction with a resolution of {\lambda}/80. Eventually we discuss the limitations of such a lens which reside essentially in losses.