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How to Win Money From the Air Force to Research Invisibility Cloaks

The Air Force is one of many government agencies that invests in invisibility research.

by Kaleigh Rogers
Mar 16 2015, 5:45pm

​Image: ​Tony Fischer/Flickr

​When it comes to super powers, there are two favored options: flight and invisibility. Since the Air Force already has the whole flight thing down, it's understandable it would want to pursue the ability to disappear.

The Air Force Office of Scientific Research provides grants to all kinds of scientific pursuits from developing ultralight mate​rials to the effects of g​roup bias. But one are where they've invested particularly heavily is in the research and development of invisibility cloaks.

The best bet for a real-deal invisibility cloak that would give fighter jets and even people the ability to move undetected is in metamaterials: artifici​al substances that have the ability to bend a wave backwards (called negative refraction). But scientists still need to solve a lot of problems with metamaterials before we can go full Harry Potter, like how to create them on a large sca​le. The Air Force is one of many groups bankrolling these pursuits.

In 2010, the AFOSR gave the University of Zagreb in Croatia a $30,000 grant to create software to analyze whether or not a type of cylindrical-shaped cloak made of many layers of metamaterial would offer the solution to some of the scientific conundrums of invisibility. Today, the technical proposal and grant award documents were published online as the result of a Freedom of Information Act request filed in 2011.

The documents detail the goals of the project and some of the lingering questions the Air Force wanted answered, such as: "is it possible to realize a cloak with the reduced set of material properties that is entirely invisible (at least at the central frequency)?" and "is it possible to realize a cloak that is invisible to pulse excitation (i.e. to radar)?"

"Uniaxial cylindrical cloaks have recently been proposed to prevent scattering of electromagnetic waves, i.e. to render objects invisible," the documents read. "The proposed cloaks with reduced variation of constitutive parameters suffer from nonzero reflectance, i.e. they are only partly invisible. Therefore, the purpose of a 12-month effort is to develop an analysis method and the corresponding software for analyzing cylinders made from metamaterial-based concentric layers with an application to invisible cloak realization."

The results of this particular project were already publicly​ available online via the Defense Technical Information Center. The researchers at UofZ created software that was able to measure the amount of invisibility a cloak design might have and learned more about the possibilities of cylindrical cloaks, but the results weren't exactly an invisibility breakthrough.

The original proposal and grant award documents outlined modest goals for the year-long research, which seems to indicate just how eager the Air Force is for any kind of advancement in invisibility technology. And its investment is inching the research forward.

Just last year, Hao Xin, a professor of electrical and computer engineering at the University of Arizona, published fin​dings based on metamaterial research fund​ed by the AFOSR. His research that showed it was possible to create a metamaterial that has negative refraction but manages not to lose energy (from microwaves, lightwaves, or anything else hitting the material), one of the many problems standing in the way of turning metamaterials into a full-blown cloaking device.

The Air Force isn't alone in its endeavor to make sure scientists are focusing on Star Trek-worthy cloaking technology, either. The​ Navy and DAR​PA have both invested in invisibility research, while the government of China has doled out funds for 40 different invisibil​ity cloak projects.

At this rate, it's a race to see who will cross the line from theoretical to practical first. And if you're looking for some research funding, you might want to try adjusting your hypothesis to include something about invisibility. It seems like a surefire way to get some dough.