Nanostructured Metamaterial Enables Invisibility Cloak

Nano-scale fishnet-like metamaterial amplifes light rather than absorbs it

2 min read
Nanostructured Metamaterial Enables Invisibility Cloak

Clearly the most attractive super hero power for nanotechnology at the moment is invisibility. Last month we had a nano-enabled coating that managed to make aircraft invisible to radar. Now we have a metamaterial consisting of fishnet-like film containing holes about 100 nanometers in diameter that could serve as an invisibility cloak.

While I personally might be persuaded to choose Spider-like climbing abilities for my nano-enabled super hero power, invisibility does pose an attractive option.

However, invisibility is far from the point of this research conducted at the Birck Nanotechnology Center, Purdue University and appears in the August 5th edition of the journal Nature.

The Purdue researchers have addressed one of the key limitations of metamaterials in optical devices: the absorption of too much light by metals in the metamaterials.

In the article cited above Vladimir M. Shalaev, Purdue's Robert and Anne Burnett Professor of Electrical and Computer Engineering, explains "This finding is fundamental to the whole field of metamaterials,” adding "We showed that, in principle, it's feasible to conquer losses and develop these materials for many applications."

Metamaterials have tantalized researchers for years with their index of refraction at or below zero that promises extraordinary breakthroughs in the field of transformation optics. But the materials absorbed too much light. With this research, some of the applications that have been discussed for these materials are back on the table such as a “planar hyperlens” that could enable “optical microscopes 10 times more powerful and able to see objects as small as DNA.”

"What's really important is that the absorption coefficient can be as small as only one-millionth of what it was before using our approach," Shalaev said. "We can even have amplification of light instead of its absorption. Here, for the first time, we showed that metamaterials can have a negative refractive index and amplify light."

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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.


If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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