Ever just want to hide from plain sight when you’ve accidentally made a crude joke and embarrassed yourself at a party? Well, the cloak of invisibility - the idea made famous, thanks to Harry Potter, the beloved storybooks - doesn’t quite exist. At least not yet.
More recently, a group of scientists in the United Kingdom have come up with their studies that take us one step closer to invisibility. They examine the possibility to manipulate surface waves, particularly the THz and optical regime. The concepts of Transformation Optics (TO) and metamaterial are the key enablers to achieve the applied eletromagnetics, or so called, “invisibility”.
The truth is, we do not have the ability to make things simply disappear, but what we can do is to deceit and control optical perception. The information that we receive through our eyes are based on the paths traversed by light, which reflect off objects with various densities. Metamaterials were introduced just over a decade ago, and it eventually expand into being able to control parts of the electromagnetic spectrum, from microwave, to terahertz, and to infrared. This transmission medium has thus developed to have the ability to direct and control light wave propagation and transmission of specific parts of the light spectrum, as well as the electromagnetic radiation, in order to render an object into seemingly invisible.
Our future dream of being “invisible” doesn’t just stop here, another group of researchers have also came up with “Surface Wave Cloak”, made out of a gradient-andes material that consists of seven super thin layers, each possessed different electric properties. They have discovered that by shielding an object with these layers, the object is prevented from interacting with electromagnetic waves, when the object would ordinarily have caused the electromagnetic wave to be scattered. And this is not just for the mere idea of being “invisible”. In the larger sense, the “Surface Wave Cloak” could be used to reduce scattering radio waves, as well as aerospace communications. “We believe that our cloaking structure can improve existing technologies and enables future technological innovation,” said Luigi La Spada, the first author of this study. “At the moment, the main interest in surface waves is to develop solutions for reducing and mitigating important telecommunications issues.”
And yes, in theory, all of these could be used on human bodies and there have been many attempts of making a real invisibility cloak. It seems as though we are finally becoming one step closer to our expectation of the future world, or perhaps, the wizard world.