The two-dimensional lens has focusing power that is nearly equivalent to the limits defined by the laws of diffraction. “We’re presenting a new way of making lenses.” said the researchers. Federico Capasso and his team created the two-dimensional lens by first plating a very thin wafer of silicon followed by a nanometer thin layer of gold. The team then removed the gold layer such that it leaves an array of v-shaped structures uniformly spaced out in rows across the silicon wafer.
“Instead of creating phase delays as light propagates through the thickness of the material, you can create an instantaneous phase shift right at the surface of the lens. It’s extremely exciting.” they added.
The v-shaped structures would function as nanoantennas, when a laser is shined onto the lens, capturing the incoming light, holding it briefly and then releasing it. These antennas can be tuned to change the direction of light in the same way as a thick glass would but without the optical aberrations, astigmatism and coma aberrations commonly found in conventional lenses today.
According to the team, the lens operates at telecom wavelengths, as used in fiber-optic communications, and that it is scalable – from near-infrared to terahertz wavelengths, and easy to manufacture as well.
The team has published the results here.