By Cameron Chai
An international team of scientists from the French National Center for Scientific Research and the Karlsruhe Institute of Technology in Germany has developed a new prototype lens using graphene.
This prototype lens is capable of focusing an electron stream just as optical lenses focus light. It is based on the fact that a graphene layer gets strained when stretched, thus enabling it to function as a 2D lens for electrons. The study has been reported in Applied Physics Letters, a journal of the American Institute of Physics.
Graphene, a one-atom-thick carbon material, is a remarkable conductor wherein electrons traverse freely in straight lines across its surface. A theory hypothesized that highly strained graphene hinders the electron flow and alters the trajectory of electrons. Researchers believed that this phenomenon can be utilized for focusing electrons towards a fine point just as optical lenses refract or bend light towards a point.
To fabricate the prototype lens, the international research team first developed a deformed graphene carpet, which effectively covers a silicon-carbide wafer’s hexagonal nano-holes. Certain regions in graphene were subjected to strain when they formed into the hole shape in the wafer. The team discovered that the graphene lens’ focal length can be controlled by altering its geometry.
The new prototype lens paves the way to develop high-speed electronic applications wherein strained graphene can be used as a transport medium to exchange information between various components in a circuit. The new technique allows electrons to flow freely just as light moves in a vacuum, which is contrary to conventional information exchange where the path of electrons traversing cables needs a short to cross.