A real invisibility cloak will likely remain science fiction for quite a while - or possibly forever - but scientists at the University of California in Berkeley say they've come one step closer. The researchers claim they have developed a new nano-material that can bend light around 3D objects:
The findings, by scientists led by Xiang Zhang, were published in the journals Nature and Science.
The light-bending effect relies on reversing refraction, the effect that makes a straw placed in water appear bent.
Previous efforts have shown this negative refraction effect using microwaves—a wavelength far longer than humans can see.
The new materials instead work at wavelengths around those used in the telecommunications industry—much nearer to the visible part of the spectrum.
Two different teams led by Zhang made objects made of so-called metamaterials—artificial structures with features smaller than the wavelength of light that give the materials their unusual properties.
One approach used nanometre-scale stacks of silver and magnesium fluoride in a "fishnet" structure, while another made use of nanowires made of silver.
Light is neither absorbed nor reflected by the objects, passing "like water flowing around a rock," according to the researchers. As a result, only the light from behind the objects can be seen.
This new material could be used to make better microscopes and might also have applications in telecommunications devices.