By using plasmons to “wiggle” a free electron in a sheet of graphene, researchers at the Massachusetts Institute of Technology (MIT) have developed a new method for generating X-rays. The discovered phenomenon could lead to more compact, tunable X-ray devices made of graphene.
MIT's finding, based on a new theory backed by exact simulations, shows that a sheet of graphene – a two-dimensional form of pure carbon – could generate surface waves called plasmons when the sheet is struck by photons from a laser beam. The plasmons, in turn, could be triggered to generate a sharp pulse of radiation, tuned to wavelengths anywhere from infrared light to X-rays.
The radiation produced by the system would be of a uniform wavelength and tightly aligned, similar to that from a laser beam. The researchers say the laser-like radiation could potentially enable lower-dose X-ray systems in the future, making them safer.
Such beams could have applications in crystallography, the team says, which is used in many scientific fields to determine the precise atomic structure of molecules. Because of its tight, narrow beam, the system might also allow more precise pinpointing of medical and dental X-rays, thus potentially reducing the radiation dose received by a patient.
