Scientists in the UK are a big step closer to developing an invisibility cloak using a flexible film made of metamaterials.
A new study, published in the New Journal of Physics, explains that the film works by manipulating light that interrupts and channels the flow of light at a fundamental level. Until now, metamaterials have not been used with visible light as it is easier to construct them with larger structures, reflecting a longer wavelength of light. In 2006, American scientists at Duke University, North Carolina, made a cloak in a similar fashion, that worked by steering microwaves around an object. To reflect visible light, the structures need to be as small as the waves’ length. This means that instead of using brittle silicon layers, a polymer of nanostructures are used which are so tiny, they are pushing the boundaries of manufacturing.
A metamaterial is an artificial material engineered to provide properties which may not be readily available in nature. In this instance, the film is made from tiny, repeating structures of simple electronic components, usually capacitors and inductors, making up several layers of ‘fishnets’. This makes the film flexible and durable with many possible applications.
Aside from the obvious Harry Potter marauders’ function, and depending on how sensitive the films are to movement, they could be used for contact lenses or handheld camera lenses. For contact lenses, the film would obviously need to resist movement, but for camera lenses the film would need to be more ductile and less resistant to bending.
Professor Ortwin Hess, Leverhulme Chair in Metamaterials (Imperial College London), has said this is “a huge step forward in many ways… It clearly isn’t an invisibility cloak yet, but that’s the huge goal”.