The Loh Down On Science

Invisibility

Mercer 8805

Jason Valentine/UC Berkeley

Top is a schematic of the first 3-D "fishnet" metamaterial that can achieve a negative index of refraction at optical frequencies. Below is a scanning electron microscope image of the fabricated structure, developed by UC Berkeley researchers. The alternating layers form small circuits that can bend light backwards.

UC Berkeley scientists find a way to make objects disappear.

Talk about feeling invisible!

This is Sandra Tsing Loh, with the Loh Down on Science

Shedding light on, well, SHEDDING light.

We see objects only because light waves--full of photons-- bounce off them. If you could stop an object from scattering those pesky photons, would it DISAPPEAR?

Scientists at the University of California at Berkeley gave it a try.

To create their invisibility material, they first produced a dozen imperceptably thin sheets of magnesium fluoride. That's the stuff that makes eyeglasses antireflective.

Then they stacked these in alternating layers with sheets of silver. The result? A technological sandwich one hundred times thinner than a hair.

After laser-cutting fishnet-like holes into it, the so-called "metamaterial" was ready for action.

When they blasted a slice with light, the energy was diverted AROUND the material, like river water around a rock, instead of being SCATTERED. Voila! Invisibility!

Alas, the process only worked using wavelengths longer than those we humans can see.

So while the technology will soon give digital images eye-popping resolution, and computers lightning-fast circuits--! Still no cloak of invisibility available at Wal-Mart. Oh, well. Next year.


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