Graphene amplifier unlocks hidden frequencies in the electromagnetic spectrum


Light in the THz frequencies hits the ‘sandwich’ and is reflected with additional energy. Credit: Loughborough University

Researchers have created a unique device which will unlock the elusive terahertz wavelengths and make revolutionary new technologies possible.

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. The conundrum is known in scientific circles as the “terahertz gap.”

Being able to detect and amplify THz waves (T-rays) would open up a new era of medical, communications, satellite, cosmological and other technologies. One major application would be as a safe, non-destructive alternative to X-rays. However, until now, the wavelengths, which range between 3mm and 30μm, have proved impossible to use due to relatively weak signals from all existing sources.

A team of physicists has created a new type of optical transistor—a working THz amplifier—using graphene and a high-temperature superconductor. The physics behind the simple amplifier relies on the properties of graphene, which is transparent and is not sensitive to light and whose electrons have no mass. It is made up of two layers of graphene and a superconductor that trap the graphene massless electrons between them like a sandwich.

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