New nanostructured materials break the old limits of optical lenses
Source: “Far-Field Optical Hyperlens Magnifying Sub-Diffraction-Limited Objects”
Xiang Zhang et al.
Science 315: 1686
Results: Researchers at the University of California, Berkeley, have developed a lens that can resolve details too small for conventional optical microscopes. Using it, they could distinguish two parallel lines 130 nanometers apart; seen through a conventional microscope, the lines looked like a single, thick line.
Why it matters: Light-based devices such as optical microscopes have long been limited to resolving or producing features half the wavelength of the light being used. Thus visible light cannot resolve anything smaller than about 200 nanometers. The new lens could make it possible to observe cellular processes never before seen. It could also be used to project images with extremely fine features, increasing the precision of photolithography or enabling much more data to be crammed onto a DVD.
Methods: The researchers carved a valley shaped like a half-cylinder into a piece of quartz. They then deposited alternating layers of silver and aluminum oxide on the walls of the cylinder. Each layer was just 35 nanometers thick and took the curved shape of the quartz. This arrangement enables the lens to gather more visual information about the object being viewed, which it then passes on to an otherwise conventional microscope.
Next Steps: So far, the lens can be used to view only things in contact with the bottom of its U-shaped valley. It should be possible to build a version of it that does not need to touch the object being viewed.