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Spotlight: Bringing Invisibility Cloaks to Reality

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Researchers are working to create a new design for the Harry Potter-esque invisibility cloak, which will conceal objects, making them more difficult for adversaries to detect.

Researchers are working to create a new design for the Harry Potter-esque invisibility cloak, which will conceal objects, making them more difficult for adversaries to detect.

Scientists are working on creating a new design for a technology that redefines what the public views as imaginary. Inspired by the well-known Invisibility Cloak from Harry Potter, electrical engineers at the University of California, San Diego have created a new design for their cloaking device, using a Teflon substrate, studded with cylinders of ceramic, that is thinner than any prior development and does not alter the brightness of light around concealed objects. The Teflon has a low refractive index, while the ceramic’s refractive index is higher, which allows light to be dispersed through the sheet without any absorption. [1] Compared to an invisibility cloak, this technology has not only the ability to conceal, but the ability to increase optical communication signal speed and to collect solar energy. [2]

The goal of this design is to create devices that make any object appear invisible by scattering the electromagnetic waves, such as light and radar, off an object making it less detectable to these wave frequencies. Metamaterial that surrounds the target is able to force light to bypass a region of space, which effectively “cloaks” the object, making it isolated from incoming electromagnetic waves. [3]

Prior developments to this technology needed many layers in order to cover an object, resulting in a very thick layer that enclosed the object. With this new, super-thin design, this technology has the capability to better hide the three-dimensionality and shadow of an object. Additionally, this new cloaking device addresses the issue with the brightness of the space behind them. The University of California has achieved a cloak that won’t reduce any intensity when light is reflected so the concealed object will remain undetectable and will appear completely flat to an observer’s eyes. [2]

"Invisibility may seem like magic at first, but its underlying concepts are familiar to everyone. All it requires is a clever manipulation of our perception," said Boubacar Kanté, a professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering and the senior author of the study. "Full invisibility still seems beyond reach today, but it might become a reality in the near future thanks to recent progress in cloaking devices." [2]

An extremely thin cloaking devise is designed using dielectric materials. The cloak is a thin Teflon sheet (light blue) embedded with many small, cylindrical ceramic particles (dark blue). (Photo courtesy of Li-Yi Hsu/University of California, San Diego)

An extremely thin cloaking devise is designed using dielectric materials. The cloak is a thin Teflon sheet (light blue) embedded with many small, cylindrical ceramic particles (dark blue). (Photo courtesy of Li-Yi Hsu/University of California, San Diego)

Having the ability to create ultimate stealth protection for anything over a battlefield or warzone provides enormous military advantage over the adversary. In theory, creating a cloaking device would be used to conceal larger objects. This cloaking device would be valuable to many technologies, including unmanned air vehicles (UAVs) due to the capability to disappear from view and leaving no visual, electronic or infrared signature for an enemy to detect. [4] Creating the effect of an invisibility cloak offers a real-world solution to concealment, which can provide the military with air superiority. While this cloak has numerous applications for the military, this technology will create a ripple effect beyond the battlefield that will improve the performance of other diverse applications.

"Doing whatever we want with light waves is really exciting," said Kanté. "Using this technology, we can do more than make things invisible. We can change the way light waves are being reflected at will and ultimately focus a large area of sunlight onto a solar power tower, like what a solar concentrator does. We also expect this technology to have applications in optics, interior design and art." [2]

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References:

  1. Sklar, P. (2015). Scientists make a breakthrough in invisibility cloak technology. Escapist Magazine.
  2. Engineers give invisibility cloaks a slimmer design. (2015). ScienceDaily.
  3. Hsu, L.Y., Lepetit, T., & Kanté, B. (2015). Extremely thin dielectric metasurface for carpet cloaking. Progress in Electromagnetics Research, 152, 33-40.
  4. Toensmeier, P. (2012). Technologies evolving to cloak battlefield vehicles from sensors.Aviation Week Network.