Day 100: Berkeley Lab gets us closer to “The Invisible Man”

Wow, 100 blog posts in 100 days … this has been big fun! I started this intense blogging effort in late January, when the economic slow-down made an acute showing in media outlets. I wasn’t getting paid assignments for a while, and I found myself without a regular outlet for what I love to do most: write about science. So I decided to utilize my own website! Through blogging, I’ve learned a lot about this fascinating realm called the blogosphere and explored social media outlets like Twitter. Every day, I’ve gotten to indulge my nerdy love of all sorts of science. Because I was so actively seeking story ideas, I ended up being able to propose more stories to my paying outlets (most of which have now rebounded significantly from the lull), and I even broke into a couple of new outlets, including Universe Today and Scientific American. 

A lot of people have asked me what happens after the “100 Days.” The fact is, I really like blogging. I’ll continue to do it, but not every day. And certainly not on the weekends, when nobody’s reading! The blog’s new name will be unveiled after a brief break, while I enjoy the rest of my road trip with my dad to see my two brothers (right now we’re with the one in Florida). 

I might not post another entry until Thursday … 

Or maybe I will, and you just won’t see it.

Why? Because maybe I’ll see about borrowing this new invisibility cloak, that’s been created by researchers with Berkeley Lab and the University of California (UC) Berkeley.

Seriously! Xiang Zhang, a principal investigator with Berkeley Lab’s Materials Sciences Division and director of UC Berkeley’s Nano-scale Science and Engineering Center, has created a “carpet cloak” from nanostructured silicon that conceals the presence of objects placed under it.  

The rest of this post, Day 100 of “100 Days of Science,” will be about the amazing work of Zhang’s team, which takes me back to the days of The Invisible Man by H.G. Wells and a fifth grade teacher, who once said anything man can imagine, we will eventually be able to do. 

These three images depict how light striking an object covered with the carpet cloak acts as if there were no object being concealed on the flat surface. In essence, the object has become invisible. Image by Thomas Zentgraf.

The new technology isn’t quite up to H. G. Wells’ ideal. The carpet itself can still be seen — but the bulge of the object underneath it disappears from view. Shining a beam of light on the bulge shows a reflection identical to that of a beam reflected from a flat surface, meaning the object itself has essentially been rendered invisible.

“We have come up with a new solution to the problem of invisibility based on the use of dielectric (nonconducting) materials,” Zhang said in a press release. “Our optical cloak not only suggests that true invisibility materials are within reach, it also represents a major step towards transformation optics, opening the door to manipulating light at will for the creation of powerful new microscopes and faster computers.”

Zhang and his team published their results in the journal Nature Materials.

Previous work by Zhang and his group with invisibility devices involved complex metamaterials – composites of metals and dielectrics whose extraordinary optical properties arise from their unique structure rather than their composition.

With these metallic metamaterials, Zhang and his group demonstrated that light can be bent backwards, a property unprecedented in nature. But the metal elements absorb too much light to achieve invisibility. The new cloak is made exclusively from dielectric materials, which are often transparent at optical frequencies.

So far, the cloak has been tested on a very small scale and in a part of the light spectrum that we don’t see — the infrared.

Because of its all-dielectric composition and design, Zhang says the cloak is relatively easy to fabricate and should be upwardly scalable. He is also optimistic that with more precise fabrication this all dielectric approach to cloaking should yield a material that operates for visible light – in other words, true invisibility to the naked eye.

“In this experiment, we have demonstrated a proof of concept for optical cloaking that works well in two dimensions,” Zhang said. “Our next goal is to realize a cloak for all three dimensions, extending the transformation optics into potential applications.”

Source: Eurekalert. See also the Berkeley Lab ‘s website.