Researchers create metamaterial lens with 10 times more power

Researchers at the University of Sydney have developed a lens with 10x the resolution of any other current lens. Writing about their work in the journal Nature Communications, the team explained that the lens is a metamaterial - a material with completely new properties not found in nature.

“Using conventional materials, the resolution of focusing and imaging devices is limited by diffraction to about half the wavelength of light, as high spatial frequencies do not propagate in isotropic materials,” the researchers wrote.

“Wire array metamaterials, because of their extreme anisotropy, can beat this limit; however, focusing with these has only been demonstrated up to microwave frequencies and using propagation over a few wavelengths only.”

The new lens, made of plastic and metal through fibre-optic manufacturing technology, uses terahertz waves - electromagnetic waves with frequencies higher than microwaves but lower than infrared radiation and visible light. It operates in a region of the spectrum where very few other optical tools are available and all of them have limitations.

“If we think of this in comparison to an X-ray which allows us to see inside objects at a high resolution but with associated danger from radiation, by contrast our metamaterial lens allows us not only to see through some opaque materials, but also to gather information on their chemical composition, and even information on interaction between certain molecules, without the danger of X-rays,” said lead author Alessandro Tuniz.

This means the lens is suited to analysing the delivery of drugs to cells, which is crucial to medical research. Its powerful resolution means researchers can “unlock previously inaccessible information on the structure of molecules, their chemical make-up and the presence of certain proteins”, said Tuniz.

“This opens up an entirely new tool for biological studies,” Tuniz continued. “It could allow earlier skin cancer diagnosis, because smaller melanomas can be recognised. For breast cancer, it can also be used to more accurately check that all traces of a tumour have been cut out during surgery.”

The potential to create a high-power lens was spotted almost a decade ago, but it has taken until now to make the lens on a useful scale, a thousand times smaller than the early experimental models. Tuniz explained, “The difficulty was making large quantities of matter structured on a micrometric scale.”

Researcher Dr Boris Kuhlmey said, “Creating metamaterials is a cutting-edge area of science with a massive range of potential uses from aerospace to solar power, telecommunications to defence.

“This is one of the first times a metamaterial with a real-world application, quickly able to be realised, has been feasible. Within the next two to three years, new terahertz microscopes that are 10 times more powerful than current ones will be possible using our metamaterial.”

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