Catching light in a graphene net

An international team of physicists led by US researcher Dmitri Basov, of the University of California, demonstrated that light can be caught and controlled within the two dimensional lattice of wonder-material graphene.

Theory has suggested that long wavelength – infrared – photons could be caught and moved through graphene at much less than the velocity of light. The photons were expected to be slowed down by their interactions with excited electrons in the graphene structure, producing a hybrid particle known as a plasmon.

Until now, researchers have been unable to study the plasmons experimentally, because the IR photons didn’t have enough energy to excite them. However, Basov and his team of researchers have discovered that a tiny mental pin – whose tip measures mere nanometres – can act a bit like a lightning rod, focussing all the incident photons in a small region. This raises the momentum of the IR photons significantly – 60 time, per the press release here - which is enough to "launch plasmonic waves along the graphene layer".

"It is even possible to control the light waves within the lattice," says Dr. Fritz Keilmann, who works at the Ludwig-Maximilians-Universitaet, the Center for Nanoscience, and the Max Planck Institute for Quantum Optics. "It might even be possible to develop computers whose graphene transistors could be switched both optically and electrically," he added.

This is because the light waves in the graphene can be controlled by electric fields and currents. This suggests that the light could be electrically tunable, leading to switching times of less than a picosecond.

The work, along with similar research from a Spanish group, appears in the current issue of the journal Nature.