Grbic and colleagues have a variety of uses for their new lenses planned, including focusing light into smaller spots during photolithography to etch smaller features onto computer chips. The lenses could also help refine a technique to transfer power wirelessly developed in 2006. The new lenses could create more energy-dense beams of the electromagnetic waves used to transfer power, Grbic says. Nader Engheta of the University of Pennsylvania in Philadelphia, US, agrees, saying the new design has "exciting potential." But the more complex metamaterial lenses will likely be more applicable to more diverse applications, he adds.
Visible light has wavelengths of 380 to 750 nm. Half of those wavelengths is 190 to 375 nanometers. Ten times better is 19-38 nanometers.
The new lens is a 127-micrometer-thick plate of teflon and ceramic with a copper topping. "The beauty of these is that they're planar," Grbic says, "they're easy to fabricate." The lenses can be made through a single step of photolithography, the process used to etch computer chips.
Anthony Grbic, Lei Jiang and Roberto Merlin at the University of Michigan in Ann Arbor, US, have now successfully made a much simpler design, first theorised last year.
By selectively etching away the copper, Grbic and colleagues created many capacitors sandwiched together. Capacitors are typically used in electronics for storing electric charge for short periods.
In the lens, the capacitors instead interact directly with electromagnetic waves like light. This sets up currents in the capacitors that focus the waves passing through the lens into a point 20 times smaller than their wavelength. That is 10 times tighter than a conventional lens can achieve, hampered by the diffraction limit.