Read more at: http://phys.org/news/2013-10-graphene-emit-laser.html#jCp
Graphene is considered the jack-of-all-trades of materials science: The two-dimensional honeycomb-shaped lattice made up of carbon atoms is stronger than steel and exhibits extremely high charge carrier mobilities. It is also transparent, lightweight and flexible. No wonder that there are plenty of applications for it – for example, in very fast transistors and flexible displays. A team headed by scientists from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg have demonstrated that it also meets an important condition for use in novel lasers for terahertz pulses with long wavelengths. The direct emission of terahertz radiation would be useful in science, but no laser has yet been developed which can provide it. Theoretical studies have previously suggested that it could be possible with graphene. However, there were well-founded doubts - which the team in Hamburg has now dispelled. At the same time, the scientists discovered that the scope of application for graphene has its limitations though: in further measurements, they showed that the material cannot be used for efficient light harvesting in solar cells.
It can't as far as we know at this time. But that could change. To read more, click here.