A new lens for focusing terahertz radiation has a resolution of 1/28th wave—10 times the resolution of any previous terahertz lens. Developed at the University of Sydney (Australia), the lens could facilitate biophotonics research. In addition to seeing through some opaque materials, the lens can gather information on chemical composition and interaction between certain molecules. This makes the lens well suited to analyzing the delivery of drugs to cells.
The advance "means we can unlock previously inaccessible information on the structure of molecules, their chemical make-up, and the presence of certain proteins," says Alessandro Tuniz, lead author of a paper describing the work.1 "This opens up an entirely new tool for biological studies. It could allow earlier skin cancer diagnosis because smaller melanomas can be recognized. For breast cancer, it can also be used to more accurately check that all traces of a tumor have been cut out during surgery."
The wire-array metamaterial structure of the lens allows it to propagate near-field information over a distance of hundreds of wavelengths. The anisotropic metamaterial contains straight and tapered wire arrays made of plastic and metal; previously, such wire arrays were demonstrated only at much lower microwave frequencies.
A major challenge is making these materials on a scale that is useful. According to Boris Kuhlmey, one of the researchers, "This is one of the first times a [terahertz] metamaterial with a real-world application, quickly able to be realized, 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."
1. A. Tuniz et al., Nat. Comm., 4, 2706 (2013); doi:10.1038/ncomms3706.