Metamagnetics with rainbow colors

Wenshan Cai,Vladimir P Drachev,Vladimir M Shalaev,Hsiao-Kuan Yuan,Alexander V Kildishev,Vashista C De Silva,Uday K Chettiar

doi:10.1364/oe.15.003333

Abstract

A family of coupled nanostrips with varying dimensions is demonstrated exhibiting optical magnetic responses across the whole visible spectrum, from red to blue. We refer to such a phenomenon as rainbow magnetism. The experimental and analytical studies of such structures provide us with a universal building block and a general recipe for producing controllable optical magnetism for various practical implementations.

Highlights

In optics, the magnetic response of most natural materials is very small in comparison to the dielectric susceptibility, limiting the interaction of atoms mainly to the electric component of light and leaving the magnetic component largely unexploited
A family of coupled nanostrips with varying dimensions is demonstrated exhibiting optical magnetic responses across the whole visible spectrum, from red to blue. We refer to such a phenomenon as rainbow magnetism
The experimental and analytical studies of such structures provide us with a universal building block and a general recipe for producing controllable optical magnetism for various practical implementations

Summary

Introduction

The magnetic response (susceptibility) of most natural materials is very small in comparison to the dielectric susceptibility, limiting the interaction of atoms mainly to the electric component of light and leaving the magnetic component largely unexploited. Other structures like coupled nanorods [8] or nanostrips [9,10,11] are preferred because there are intrinsic limits to scaling SRR sizes in order to exhibit a magnetic response in the optical range [12,13]. We study the general resonant properties of magnetic metamaterials consisting of arrays of paired thin silver strips. The magnetism in such a structure has been discussed theoretically [9, 10] and was recently demonstrated experimentally at the very red end of the visible range [14]. We demonstrate structures with magnetic responses across the whole visible spectrum by creating a family of paired-strip samples with varying geometries. We note that any controllable optical magnetic responses, whether they have a positive or negative permeability, are important for various implementations such as negative refraction [15,16,17], subwavelength waveguides and antennas [18,19], spectral selective filters [20], total external reflection [21], and electromagnetic cloaking devices [22,23]

Experimental characterizations

Simulations

Dependence of magnetic resonance on geometries

Conclusion