Optical Metamagnetism and Negative Index Metamaterials

TL;DR

This paper reviews advances in optical metamaterials, highlighting the fabrication of negative index materials at visible wavelengths, including a record observation at 710 nm, and discusses associated fabrication challenges.

Contribution

It reports the first demonstration of negative index behavior at 710 nm in the visible spectrum and analyzes fabrication limitations affecting optical properties.

Findings

Negative index behavior observed at 710 nm wavelength.

Fabrication challenges include surface roughness impacting optical properties.

Progress in creating optical metamaterials with artificial magnetic response.

Abstract

A new class of artificially structured materials called metamaterials makes it possible to achieve electromagnetic properties that do not exist in nature. In this paper we review the recent progress made in the area of optical metamaterials. It was predicted that nanostructured metamaterials could provide us with artificial magnetic response and negative refractive index at optical frequencies. To date, optical metamagnetics have been already fabricated to demonstrate artificial magnetic response in the infrared and across the entire visible spectrum, while metamaterials showing negative refractive index, also called negative index materials (NIM), have been demonstrated in the infrared and at the border with the visible spectral range. Here we report the results of a sample that displays NIM behavior for red light at a wavelength of 710 nm. This is the shortest wavelength so far at which NIM behavior has been observed for light (excluding a device built on surface plasmon polaritons). We also discuss the fabrication challenges and the impact of fabrication limitations, specifically surface roughness of the fabricated structures on the optical properties of the metamaterials.