Interferometric characterization of a sub-wavelength near-infrared negative index metamaterial

Xuhuai Zhang,Marcelo Davanço,Dmitriy Korobkin,Chihhui Wu,Gennady Shvets,Chris Fietz,Thomas W Jarvis,Kara Maller,Stephen R Forrest,Xiaoqin Li

doi:10.1364/oe.18.017788

Abstract

Negative phase advance through a single layer of near-IR negative index metamaterial (NIM) is identified through interferometric measurements. The NIM unit cell, sub-wavelength in both the lateral and light propagation directions, is comprised of a pair of Au strips separated by two dielectric and one Au film. Numerical simulations show that the negative phase advance through the single-layer sample is consistent with the negative index exhibited by a bulk material comprised of multiple layers of the same structure. We also numerically demonstrate that the negative index band persists in the lossless limit.

Highlights

Negative index metamaterials (NIMs) were demonstrated, first in the microwave regime [1], and subsequently at near-infrared or higher optical frequencies [2, 3]
While there have been a number of reports of optical NIMs [4] including a recent prism refraction experiment at a wavelength of λ = 1.5μm [5], interferometric measurements of the phase advance of light through optical metamaterials [3, 6,7,8] have been rare
In the few such reports on optical NIMs [3, 6, 8], the relationship between the measured phase advance through samples consisting of only a single layer of unit cells and that expected from transmission through hypothetical multi-layer bulk NIMs was not investigated

Summary

Introduction

Negative index metamaterials (NIMs) were demonstrated, first in the microwave regime [1], and subsequently at near-infrared or higher optical frequencies [2, 3]. While there have been a number of reports of optical NIMs [4] including a recent prism refraction experiment at a wavelength of λ = 1.5μm [5], interferometric measurements of the phase advance of light through optical metamaterials [3, 6,7,8] have been rare In the few such reports on optical NIMs [3, 6, 8], the relationship between the measured phase advance through samples consisting of only a single layer of unit cells and that expected from transmission through hypothetical multi-layer bulk NIMs was not investigated. Using numerical simulations that include artificially low metallic losses, we confirm that the negative effective index exhibited by this structure is not the result of high losses at optical frequencies [13]

Experiment: sample and interferometric characterization

Results and discussion

Conclusions