Additive Manufacturing Technology Brings Scientists One Step Closer to Creating an ‘Invisibility Cloak’

An official survey revealed that two out of three people, when asked what magical power or item they would choose if they had to pick one, would take an invisibility cloak over anything else. And who can blame them? It let Harry Potter get away with things that would have immediately gotten him expelled if he had been caught. Imagine the havoc that could be wreaked – I mean, the good and productive things that could be accomplished – with one of those things. In the spirit of full disclosure, it wasn’t exactly an “official” survey, more like a few nerds sitting around a bonfire, but I still consider it an accurate representation of the magical preferences of the general populace.

Now comes the news, revealing yet again the fine line between science and magic, that scientists have come a step closer to creating an actual invisibility cloak. Before you freak out and assault an owl by trying to tie mail to its foot, I have to tell you that this Muggle version of the invisibility cloak is a bit different from Harry Potter’s. It can’t actually make people invisible  (sorry!) – but it can make certain objects disappear, at least where electromagnetic waves are concerned, by causing curved surfaces to appear flat.

Researchers at Queen Mary University of London (QMUL) used an additive manufacturing technology that involved coating a tennis ball-sized curved metallic surface with a nanocomposite medium consisting of seven distinct layers with varying electric properties depending on their positions. The effect of the layered nanocomposite medium, called a graded index nanocomposite, is that electromagnetic waves, which normally would scatter when striking the object, pass right over it without disruption – as though it isn’t even there.

“In this paper, we experimentally demonstrate for the first time a dielectric surface wave cloak from engineered gradient index materials to illustrate the possibility of using nanocomposites to control surface wave propagation through advanced additive manufacturing” the researchers state in their paper’s abstract. “The device is designed analytically and validated through numerical simulations and measurements, showing good agreement and performance as an effective surface wave cloak. The underlying design approach has much wider applications, which span from microwave to optics for the control of surface plasmon polaritons (SPPs) and radiation of nanoantennas,”

“The design is based upon transformation optics, a concept behind the idea of the invisibility cloak,” said Professor Yang Hao of QMUL’s School of Electronic Engineering and Computer Science. “Previous research has shown this technique working at one frequency. However, we can demonstrate that it works at a greater range of frequencies making it more useful for other engineering applications, such as nano-antennas and the aerospace industry.”

Hao is one of the authors of the recently published study “Surface Wave Cloak from Graded Refractive Index Nanocomposites.” It’s not the first time scientists have created invisibility cloak-like materials, and cloaking technologies remain under regular study, but as Hao states, QMUL’s research has the potential to take the technology further than it’s been taken before, and used for a wider range of applications. It could change the way antennae are attached to their bases, allowing antennae of varying shapes and sizes to be attached in awkward places and to different materials that weren’t possible before.

“The study and manipulation of surface waves is the key to develop technological and industrial solutions in the design of real-life platforms, for different application fields,” said Dr. Luigi La Spada, also of the School of Electronic Engineering and Computer Science. “We demonstrated a practical possibility to use nanocomposites to control surface wave propagation through advanced additive manufacturing. Perhaps most importantly, the approach used can be applied to other physical phenomena that are described by wave equations, such as acoustics. For this reason, we believe that this work has a great industrial impact.”

So while kids (and most adults, let’s be fair) may be disappointed that they still can’t access the technology to let them sneak around invisibly, the study from the QMUL researchers could result in some amazing (dare we say magical?) new applications in aerospace and engineering. Their “invisibility cloak” may not be able to hide humans from sight, but the fact remains that they actually made an object disappear.

The research is being funded by a QUEST (The quest for ultimate electromagnetics using spatial transformations) grant from the Engineering and Physical Sciences Research Council (EPSRC). Is an invisibility cloak something you dream of having? Let’s discuss over in the 3D Printing Invisibility Cloaks forum at 3DPB.com.