Graphene hybrid interacts with electromagnetic radiation

New research led by Exeter University has shown how the unique properties of graphene can be used to create artificial structures that can control and manipulate electromagnetic radiation over different wavelengths.

A team of international scientists, led by Exeter’s Prof Geoff Nash have engineered a new hybrid structure – or metamaterial – that is claimed to possess specific characteristics that are not found in natural materials.

According to the university, the team combined nano-ribbons of graphene, in which electrons are able to oscillate backwards and forwards, together with a split ring resonator, which is a type of antenna.

Careful design of these two elements leads to a system that interacts strongly with electromagnetic radiation. In these experiments the team used light with very long wavelengths to show that these new structure can be used as a type of optical switch to interrupt, and turn on and off, a beam of this light very quickly.

The collaborative international research included Dr Sergey Mikhailov at the University of Augsburg, Germany, and Prof Jérôme Faist at ETH Zurich.

In a statement, Prof Geoff Nash, from Exeter University’s Department of Engineering said: “In these novel results we demonstrate a new type of structure which can be used not only as an exciting test bed to explore the underlying new science, but that could form the basis of a range of technologically important components.” 

The research was carried out as part of the EU FET Open Project GOSFEL , which aims to develop an entirely new laser source for applications such as gas sensing.

Prof Nash said: “One of the key characteristics of our structure is that it has the effect of focussing the electromagnetic radiation into an area much smaller than its wavelength.”

“This could potentially lead to new ways of undertaking ultra-high resolution spectroscopy of, for example, bio molecules. Working with colleagues in Biosciences we are already starting to explore some of these effects, with undergraduates from our innovative interdisciplinary Natural Sciences programme, and postgraduates from the Exeter EPSRC Centre for Doctoral Training in Metamaterials.” 

The research, entitled Highly tunable hybrid metamaterials employing split-ring resonators strongly coupled to graphene surface plasmons” is published online in Nature Communications.