Flexible metamaterials the key to a working invisibility cloak?
Scottish researchers are reporting a "practical breakthrough" that could lead to the development of that most sought after of wardrobe items – the invisibility cloak. The concept of the invisibility cloak (not pictured) is based around harnessing the unique electromagnetic wave-bending properties of metamaterials, but this poses problems when it comes to creating flexible surfaces suitable for applications like clothing and contact superlenses for visual prostheses... problems which the new material design known as "Metaflex" hopes to address.
Synthetic metamaterials have a property known as a "negative refractive index" which allows light and other electromagnetic waves to be bent in a very strange way and theoretically makes it possible for objects to be made invisible. These exotic materials are being investigated in a number of fields including sonar-cloaking mechanisms for ships and submarines and magnetic shielding, but things get a little trickier when it comes to visible light because the metamaterial must cater for visible light’s smaller wavelength and be able to attach to a flexible structure (like clothing).
The new material designed by researchers from the University of St Andrews, Scotland, addresses these issues by taking meta-atoms (which make up the metamaterial) and stacking them together.
Previously meta-atoms have been designed for flat, hard surfaces (like the skin of a submarine), but using this new structure, the researchers predict that an independent, flexible material can be created.
“Metamaterials give us the ultimate handle on manipulating the behavior of light," says research team leader Dr Andrea Di Falco. "The impact of our new material Meta-flex is ubiquitous. It could be possible to use Meta-flex for creating smart fabrics and, in the paper, we show how easy it is to place Meta-flex on disposable contact lenses, showing how flexible superlenses could be used for visual prostheses.”
It all sounds like science fiction right now, but there could come a day when you'll be snapping up last seasons' invisibility cloaks on the sale rack outside Macy's.
The research is being published this week in the New Journal of Physics (co-owned by the Institute of Physics and German Physical Society).