When a supersonic aircraft goes faster than the speed of sound, it produces a shockwave or sonic boom. MIT researchers have found a similar optical effect in graphene that causes an optical boom and could provide a new way to convert electricity into light.
The light emission occurs due to two odd properties of graphene: first, light gets trapped on the surface of graphene, effectively slowing it down. In addition, electrons pass through at very high speeds. Interestingly, the speeds are nearly the same–that is, electrons and trapped light travel at almost the same speed. The researchers found a way to make the electrons move faster than the speed of light (in the graphene) and thus created Cerenkov emissions. Because of the structure of graphene, the resulting light is intense and tightly focused.
The researchers speculate that this technique could be important in building graphene-based optical chips. We’ve talked about mixed graphene and semiconductor chips before. Graphene is pretty exotic stuff. It can even fold itself.