Harvard Makes Distortion-Free Lens from Gold and Silicon, Aims for the Perfect Image (or Signal)

It appears to be a type of Fresnel Zone Plate. The percent transmittance of light will likely be a lot less than a lens, so that's the trade-off.

http://en.wikipedia.org/wiki/Zone_plate

Possibly not. Fresnel zone plates are wavelength-dependent whereas this construct is not (good from deep IR through UV). Moreover, at 60 nm thickness, the substrate plays no part other than to hold the structures in-place (and mounted in a frame, like a pellicle mirror, as a glass substrate would re-introduce chromatic abberation. Fluorite would be a better choice, but still...).

Sadly, this piece is behind a paywall, but I will have a uni library eSubscription within a few days which will grant access to this piece.

Some important details in the article are vague, but the work done so far has been using laser (monochrome) light. It's also described as a lens for telecommunications; in telecommunications the lenses work at a number discrete wavelengths, not a wide (continuous) spectrum of light like a visual camera. So the focal point may shift slightly for each wavelength, but that can be easily dealt with in the de-muliplexing.

The use of concentric rings to do phase-shifting to bring the light to a focus sounds very much like a type of zone plate. The difference between this and a conventional zone plate is that all of the light can be used with this, whereas in a zone plate half of the light is absorbed (or reflected) by the opaque zones. And also like a zone plate the substrate that supports the concentric rings is irrelevant.

Here are a few paragraphs from the article. Note it says it is scalable across a wide wavelength range, which implies (to me) it can work at any chosen discrete wavelength across this range, not at all of them at the same time.

Operating at telecom wavelengths (i.e., the range commonly used in fiber-optic communications), the new device is completely scalable, from near-infrared to terahertz wavelengths, and simple to manufacture.

[For the diagram] The colored rings show the magnitude of the phase delay corresponding to each ring. (Image courtesy of Francesco Aieta.) Flat lens offers a perfect image. Enlarge Left: A micrograph of the flat lens (diameter approximately 1 mm) made of silicon. The surface is coated with concentric rings of gold optical nanoantennas (inset) which impart different delays to the light traversing the lens.

When Capasso's group shines a laser onto the flat lens, these structures act as nanoantennas that capture the incoming light and hold onto it briefly before releasing it again. Those delays, which are precisely tuned across the surface of the lens, change the direction of the light in the same way that a thick glass lens would, with an important distinction. The flat lens eliminates optical aberrations such as the "fish-eye" effect that results from conventional wide-angle lenses.

Btw, ever notice how CDs tend to focus reflected light even for measurably flat CDs, with the focal range varying by wavelength?

No camera or lens makes a perfect image. Only a good photographer can do that, and he can do it with a 1963 Instamatic, if he wants.

Not of a retina.