What happens when you put a Luneburg lens on a silicon chip

Recently British physicists announced to the world that they managed to put a Luneburg Lens on a silicon chip. Here's why this odd bit of news could change the world.

Well, at least the world of data processing.

A Luneberg lens is a perfectly spherical lens. All parallel waves of light that hit the lens on one side are curved by the lens and brought to a single point at the other side. This means that whether light waves hit the lens at the uppermost tip, the lowermost point, or dead center, they will all be brought to a tight focus at the other end of the lens, as long as they are moving parallel to each other. To someone looking at the far side of the lens, the light will be emitted from a single point.


For those struggling to see the practical purpose of such a thing, Luneberg lenses are sometimes used as radar reflectors. Half of the lens is made reflective. Light shines in from a source and focused on a single spot at the reflective side of the lens. The reflective side pitches the light back through the lens and out to the light's origin.

Think of the way a red reflector on the back of a bike shines in a car's headlights. The same principle applies to radar, which is useful if you're a little boat in a big ocean and you don't want to get mown down by any of the big boats out there.

Since silicon chips don't engage is maritime activities, what good is it to put a Luneberg lens on one of them? Optics are already used in computing to reduce noise and process data. Precise focus will help expand that technology.

Or they'll just be used to signal ships of tiny, tiny boats.

Via Physics World and WN.com. Original scientific paper [PDF] at arxiv.

Image credit: Ulf Leonhardt


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