Graphene device bridges the terahertz gap

Terahertz waves (THz) sit between microwaves and infrared in the light frequency spectrum, but due to their low-energy scientists have been unable to harness their potential. Now, a team from the University of Loughborough have created a new type of optical transistor ­­­– a working THz amplifier – using graphene and a high-temperature semiconductor.

Professor Fedor Kusmartsev, of Loughborough’s Department of Physics, said: “The device has a very simple structure, consisting of two layers of graphene and superconductor, forming a sandwich. As the THz light falls on the sandwich it is reflected, like a mirror. The main point is that there will be more light reflected than fell on the device.” 

Being able to detect and amplify THz waves would open up a new era of medical, communications, satellite, cosmological and other technologies. One of the biggest applications would be as a safe, non-destructive alternative to X-rays.

The breakthrough – made in conjunction with researchers from Korea, China and Russia – has been published in Physical Review Letters. The team is continuing to develop the device and hopes to have prototypes ready for testing soon.

Prof Kusmartsev said they hope to have a working amplifier ready for commercialisation in about a year. He said: I expect, that with such an amplifier available we will be able to discover many mysteries of nature, for example, how chemical reactions and biological processes are going on or how our brain operates and how we think.

“The terahertz range is the last frequency of radiation to be adopted by humankind.”