When Thomas Edison first created the commercially available light bulb, after copious trial and error, he used a carbon-based filament that glowed when electricity was passed through it. Researchers looking for ways to build circuits that run on light rather than electricity have hit upon a new form of carbon, graphene, to create the world’s smallest light bulb. Graphene is a form of carbon that is one atom in width. Tiny strips of graphene emit light when electricity is passed through them, just like the filaments first produced by Edison and the modern ones made of tungsten.
The properties of graphene and how they can be used are the subject of ongoing research. One property that makes it an ideal part of photonic circuits is that graphene does not conduct heat as efficiently as conventional incandescent bulbs. That means that a graphene transistor would work pretty well as part of new devices that run on light rather than electricity.
The implications for innovations in everything from computers to handheld devices are profound. The limiting factor for conventional circuits is that electricity can only run so fast through a wire. Light, by definition, moves at the speed of light. Light can also be tuned to various wavelengths, providing a wider array of signals than the on/off 0 or 1 system that conventional electronic circuits provide. Photonic circuits using lasers and LED lights are already in use in a number of applications. The circuits using graphene lights will be the same size as conventional electronic circuits, but more efficient.