January 15, 2010 – Researchers at Northeastern U.’s Electronic Materials Research Institute have created a 3D nanolens from metamaterials to provide more accurate and detailed imaging of nanoscale objects.
Conventional lenses construct an image of an object using ordinary waves, but not the tiny subwavelength details of nano-sized objects that are carried by "evanescent" waves. Previous uses utilized amplified evanescent waves in thin metallic films or metal-dielectric layers, but were restricted to very small thicknesses (<< λ, wavelength) and thus short distances due to losses in the material.
In their new work, reported in the Jan. 11 issue of Applied Physics Letters, the Northeastern researchers arranged and packaged millions of nanowires (20nm dia.) in a way to control how light passes through the lens; by using both ordinary and evanescent waves to construct an image, the lens can depict a clear, high-resolution image of nanosized objects.
Super-resolution imaging with subwavelength resolution by the metamaterial nanolens at 1550nm. The nanolens consists of high aspect ratio metallic nanowires which are embedded in a host dielectric medium. The resolution of the lens is more than 2x better than the diffraction limit. (Image courtesy of Northeastern U.)
"This is the best superlens realized so far, and is a significant development in the field of high-resolution optical imaging," said Srinivas Sridhar, prof. and chair of physics at Northeastern, in a statement.
Sridhar claims the group already has capabilities for large-scale production of the nanolenses, and wants to begin manufacturing "in the near future," he added. End applications include biomedical imaging and lithography techniques. The work is funded by the National Science Foundation and the US Air Force.