A team of physicists from the University of Geneva (UNIGE) has measured a giant optical phenomenon in graphene. This material, the discovery of which was awarded the 2010 Nobel Prize in Physics, consists of a single layer of carbon atoms. Its exceptional properties are at the heart of global research in disciplines as diverse as engineering, biology and chemistry, with great potential for future applications. Now, contrary to all expectations, researchers have just observed a rotation of light of very great amplitude at the heart of graphene, a rotation that makes this material usable in new optical applications.
In the race to miniaturize and nano-fabricate electronic components, graphene’s potential is equal to the challenges posed by new technologies. Thanks to its extraordinary physical and chemical properties, the world’s thinnest material possesses some surprising properties. The most exceptional of these is the fact that, in graphene, the electrons that generate the electric current have a much higher speed than in a conventional material, making faster electronics a real possibility. Graphene thus represents an extremely promising alternative to conventional semiconductor materials.
A giant optical effect in an extremely thin material
Researchers at the University of Geneva have studied the optical polarization of infrared light passing through a layer of graphene under the influence of a magnet. Polarization is an important characteristic of light, and is used in camera filters, 3D cinema glasses, the lenses of certain sunglasses, known as "polarizing" lenses, and optical communications (Internet, cell phones, etc.).
In a conventional material, polarization rotation increases with sample thickness. What happens in graphene, whose thickness is that of an atom? Experiments show that the rotation is gigantic. In fact, it reflects the special nature of graphene electrons, which interact specifically with light particles.
Towards new applications
With this discovery, graphene is more than ever at the forefront of the materials of the future. The innovative results of this study make it possible to envisage the use of graphene for various electro-optical applications in the infrared range, where polarization plays a crucial role (ultrafast lasers). Unlike conventional materials, in graphene the direction and amplitude of polarization rotation can be easily and rapidly reversed. This observation of high-amplitude rotation in a single atomic layer will make it easy to miniaturize the devices currently in use.
