truly a site unseen

Archive for July 2015

Are we almost there?

The trouble with your standard present-day “invisibility cloaks” is that they’re not all that cloaky: kinda thick and inflexible, in fact. But wait:

Researchers at the University of California, San Diego, designed a carpet cloak, a device that covers an object and scatters light as if it’s hitting a flat surface instead of something three-dimensional.

The cloak is very thin — only about a tenth the size of the wavelength of the photons it’s scattering — and lossless, so there’s no dimming to give away the presence of the cloak. The scientists achieved this by using a new design and different materials. Instead of a periodic structure of metal, which absorbs light, they use two dielectric materials, a Teflon substrate studded with cylinders made of a ceramic. The ceramic has a high refractive index, and the Teflon has a low refractive index. When combined, they create a metamaterial, capable of bending light in unusual ways.

The finished product will of necessity be extremely thin:

It was designed for the microwave range, with a 0.6 cm thickness to handle 6 cm wavelengths, simply because those larger dimensions made it easier to work with. A cloak could be made for visible light but would have to be much thinner. Because the shortest wavelength the human eye perceives is slightly less than 400 nm, a cloak would have to be less than 40 nm thick, a dimension easily achievable by the photolithography processes used for making computer chips.

Still: WANT.

(Via Instapundit.)

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