Southampton University to create metamaterials centre
The University of Southampton is to establish a £6.3m centre funded primarily by the Engineering and Physical Sciences Research Council (EPSRC) to perform research that could lead to much more efficient solar cells and optical switches for the internet.
Known as photonic metamaterials because they exhibit properties not found in conventional media, the materials have surfaces covered with tiny features on the scale of tens of nanometres across. These nanostructured structured surfaces can influence both the magnetic and electrical properties of photons. The Southampton researchers, led by Professor Nikolay Zheludev, aim to create both passive metamaterials and active forms, which add substances such as the phase-change materials used in rewriteable CDs, to create new forms of data storage and sensors.
“It is a fast moving field and we want to lead it, not follow it,” said Professor Rob Eason of the University of Southampton. “The aim is to update telecoms, recording and display technologies to make them better, faster, smaller. On the nanos-scale, you can get massive enhancement of magnetic properties. By being structured at dimensions less than the wavelength of light, you can impart useful behaviours that you wouldn’t see if you had larger structures.
“These metamaterials have properties that will lead us into the 21st Century.”
Eason explained that the metamaterials can be used to control photons, making it easier for normal materials to interact with light. “Absorption and emission properties are changed dramatically when atoms are near these other structures. If you trap an atom on the surface of a metamaterial, it’s properties will shift radically.”
Scientists have proposed metamaterials as providing a way to build ‘invisibility cloaks’ that are able to steer light around solid objects to make them disappear from view. “They really only work at one wavelength of light, said Eason, adding that the Southampton team will focus on other areas over the six years that the programme will run to find out which are the most promising.
“There are six or seven areas where photonic metamaterials could have an impact,” Eason claimed. The fields include energy, as the metamaterials could be used to improve the way in which photovoltaics convert energy from light, telecoms, chemical sensing and data storage.
“Over the next six years, the idea is to do a whole slew of things and then narrow down the ones that look promising,” said Eason.
The team will use the recently built cleanroom at the university to investigate how to define features that are down to 10nm across. Other work on metamaterials has focused on longer wavelengths of light, in the infrared and terahertz spectrum, where features sizes are 1µm or above. “Our range goes roughly from visible light to a wavelength of about 2.5µm. It covers the telecom range of interest,” Eason said.
The programme will get underway at the beginning of October and, although centred on Southampton, Eason said the team will collaborate with researchers working on metamaterials at the US Department of Energy and the University of Tokyo, among others.