Graphene brings tuneable properties to terahertz devices

Researchers at Manchester University have found that graphene can be used to control the frequency of terahertz lasers, a development that may lead to safer alternatives to X-rays.

The benefit of using terahertz lasers instead of X-rays is that they can accurately scan materials without causing damage. Furthermore, by utilising the electrical properties of graphene, highly sensitive scanners for sensing minute defects in manufactured drugs, or detecting concealed weapons at airports could become more accurate and much safer for frequent use using the new technology.

The researchers, led by Dr Subhasish Chakraborty and Sir Kostya Novoselov, have reported their findings – Tuning THz lasers via graphene plasmons – in Science.

“Terahertz technologies have been somewhat ignored by industry, partly due to the complexity of creating high-power tuneable devices, as lots of different materials were necessary,” said Dr Chakraborty. “Graphene can now fill in the gaps of this technology by creating a platform to electronically control devices and flexibly engineer device output.”

According to Manchester University, the introduction of tuneable properties thanks to graphene could also potentially increase internet bandwidth capabilities up to and beyond one terabyte per second.

Sir Kostya said: “Current terahertz devices do not allow for tuneable properties, a new device would have to be made each time requirements changed, making them unattractive on an industrial scale.

“Graphene however, can allow for terahertz devices to be switched on and off, as well as altering their state.”

Graphene – a one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice – was discovered at Manchester University in 2004.

Pioneering work with graphene at Manchester University led to Sir Kostya and colleague Prof Andre Geim being awarded the Nobel Prize for Physics in 2010.