Towards subdiffraction imaging with wire array metamaterial hyperlenses at MIR frequencies.

Richard Lwin,Juliano G Hayashi,Darren D Hudson,Sergei Antipov,Alessio Stefani,Stuart D Jackson,Boris T Kuhlmey,Alexander Argyros,Simon Fleming

doi:10.1364/oe.27.021420

Abstract

We describe the fabrication of metamaterial magnifying hyperlenses with subwavelength wire array structures for operation in the mid-infrared (around 3 μm). The metadevices are composed of approximately 500 tin wires embedded in soda-lime glass, where the metallic wires vary in diameter from 500 nm to 1.2 μm along the tapered structure. The modeling of the hyperlenses indicates that the expected overall losses for the high spatial frequency modes in such metadevices are between 20 dB to 45 dB, depending on the structural parameters selected, being promising candidates for far-field subdiffraction imaging in the mid-infrared. Initial far-field subdiffraction imaging attempts are described, and the problems encountered discussed.

Highlights

A combination of conducting/dielectric layers or a subwavelength array of metallic wires embedded in a dielectric exhibit hyperbolic dispersion due to the high anisotropy of the medium [1]
The modeling of the hyperlenses indicates that the expected overall losses for the high spatial frequency modes in such metadevices are between 20 dB to 45 dB, depending on the structural parameters selected, being promising candidates for far-field subdiffraction imaging in the mid-infrared
We have numerically investigated the optical losses of wire array metamaterials to understand the typical tapering transitions required to achieve hyperlenses with losses in the MIR that could permit successful imaging experiments

Summary

Introduction

A combination of conducting/dielectric layers or a subwavelength array of metallic wires embedded in a dielectric exhibit hyperbolic dispersion due to the high anisotropy of the medium [1]. We propose a wire array tapered hyperlens structure that could lead to far-field subdiffraction imaging in the MIR and analyze its optical loss as a function of overall length for two different material combinations (tin/soda-lime and gold/silica). Such numerical modeling indicates the typical length and structural transition required to limit the hyperlenses’ overall losses to 50 dB when operating in the MIR. We describe far-field subdiffraction imaging attempts with the fabricated hyperlenses, and discuss in detail the problems encountered and possible solutions

Overall loss estimation of wire array hyperlenses in the MIR

Hyperlens fabrication

Far-field imaging attempt with wire array hyperlenses in the MIR

Conclusion