Experimental demonstration of non-magnetic metamaterial cloak at microwave frequencies

TL;DR

This paper reports the first experimental demonstration of a non-magnetic metamaterial cloak at microwave frequencies, achieving a large concealed region and paving the way for optical cloaking applications.

Contribution

It introduces a non-magnetic cloaking device at microwave frequencies with experimental validation, overcoming challenges of artificial magnetism in optics.

Findings

Successful mapping of magnetic fields around the cloak

Largest experimentally reported concealed region (4.4 wavelengths)

Potential scalability to optical frequencies

Abstract

Metamaterials have paved the way to unprecedented control of the electromagnetic field1,2. The conjunction with space coordinate transformation has led to a novel "relativity inspired" approach for the control of light propagation. "Invisibility cloak" is the most fascinating proposed devices3,4. However, the realized structures up to now used a graded "metamagnetic" so as to achieve the cloaking function11. Artificial magnetism is however still very challenging to obtain in optics despite the currently promising building blocks13-17, not suited for optical cloaking. We report here the first experimental demonstration of non-magnetic cloak at microwave frequencies by direct mapping of the magnetic field together with the first experimental characterization of a cloak in free space configuration. The diameter of the concealed region is as big as 4.4 in wavelength units, the biggest reported experimentally so far. The principle can be scaled down to optical domain while keeping the compatibility with current nanofabrication technologies.