An international team of physicists discovered that the polarization of light can be rotated by almost 6° as it passes through a single sheet of graphene in a magnetic field. The team believes that graphene could be exploited in new devices that switch light using electric and magnetic fields.
Graphene was not expected to generate a large rotation because the angle is proportional to the thickness of the material in magnetic fields, and Graphene is just one atomic layer thick.
One important benefit of making such magneto-optical devices from graphene is that the direction of the Faraday rotation can be reversed by simply applying an electric field to the graphene. In other materials, in contrast, this is only possible by reversing the applied magnetic field, which is a slower and more complicated process.