Scientists might be one step closer to making Harry Potter a reality. A recent study published in Science claims that researchers at UC Berkeley have designed “an ultrathin invisibility skin cloak for visible light.”1 In other words, we might have that Harry Potter-style invisibility cloak of our dreams.
Invisibility is defined as the state of being unseen. Light plays an essential role in how we see things; therefore, light and visibility (or invisibility) go hand in hand. Objects are visible because they reflect or absorb light, illuminating the object’s shape.2 Previous attempts at invisibility cloaks tried to redirect light around the object; however, this required too much material, making the cloak bulky and impractical.
The new and improved cloak is 80 nanometers thick and covered with tiny gold nanoantennas that distort light waves on a 3-D object, making it appear as if light is reflecting off a flat surface.3 For now, this flexible micro cloak covers only 1,300 square microns (the size of a few biological cells) and is effective only at 730-nanometer light. In addition, the nanoantenna patterns are precisely engineered to match the object’s surface, so the object must be stationary. The object also cannot be too large or too sharp, as any shadows cannot be hidden (shadows lack light, so they can’t be corrected by this invisibility technique).
Nevertheless, the cloak’s creators are confident the technology can be improved and scaled up.3 A cloak made out of this gold metamaterial could one day be used in clothing. It could even be designed to make one object appear like another, rather than simply hiding it. This could provide breakthroughs in military strategy (disguising fighter jets as freighters) or covert operations (changing one’s facial features). Currently the cloak provides only passive camouflage, but researchers are already working on making the cloak adaptable to different conditions.
In the end, all invisibility requires is a “clever manipulation of our perception.”4 Full invisibility is still beyond our reach, but it will certainly become accessible in the near future. Reality just got a bit more magical.
Jenny Ren is a sophomore from Jones College at Rice University.
1. Ni, X., Wong, Z., Mrejen, M., Wang, Y., & Zhang, X. An ultrathin invisibility cloak for visible light. Science 2015, 349, 1310-1314.
2. Khan, A. Can’t believe your eyes? Scientists build tiny invisibility cloak. http://www.latimes.com/science/sciencenow/la-sci-sn-tiny-invisibility-cloak-gold-metamaterial-20150917-story.html (accessed 9/25/15), part of Los Angeles Times.
3. US scientists make tiny invisibility cloak. http://www.nation.co.ke/lifestyle/health/US-scientists-make-tiny-invisibility-cloak/-/1954202/2875888/-/d1nq7s/-/index.html (accessed 9/25/15), part of Daily Nation.
4. Sifferlin, A. Scientists are getting closer to an invisibility cloak. http://time.com/4042506/invisibility-cloak/ (accessed 9/21/15), part of Time.