Researchers at UC Berkeley have created a foldable, amazingly thin invisibility cloak, which can enclose around microscopic items of any shape thereby making them unnoticeable in the visible spectrum. In its present form, the technology might be helpful in optical computing or even in shrouding secret microelectronic components from snooping eyes; however, as reported by the scientists involved, it can as well increase in size with relative ease.
Objects are noticeable to us due to a tiny portion of the light, which hits them is distributed towards our retinas. Invisibility cloaks may make objects vanish from sight by taking advantage of the uncommon optical properties of what are referred to as metamaterials. These unique man-made compounds may manipulate light in special ways to steer it around the cloak’s surface, to ensure that no light is reflected from it or even the object it is shielding.
Cloaks have been created to work in the visible, ultraviolet and infrared Parts of the electromagnetic spectrum. But while successful in bending light around a subject, these gadgets as well disrupt the phase of the electromagnetic wave; so, whilst the object stays concealed since no light is reflected off it, the cloak itself may still be seen through specialized instruments. What is more, these gadgets as well are often quite cumbersome and difficult to increase in size.
The cloak utilizes arrays of gold nanoantennas, with each one influencing the phase of the light wave, which is spread off the cloak. When a cloaked object is irradiated by 730-nanometer wavelength (deep red) light, the antennas make the cloak function as a perfectly flat mirror, no matter its existing form.
Xiang and team analyzed their creation by wrapping the cloak around a cell-sized object with an extremely uneven shape. Naturally, when red light hit the cloak, it reflected off its surface as though off a flat mirror, making the object underneath it undetectable even by phase-sensitive identification. When the polarization of the nanoantennas was changed, the cloaking effect ceased completed.
While the capability to pull a Harry Potter with a large-scale model of this cloak might be years away, the existing model may already find use in concealing sensitive designs of electronic components or even facilitating the growth of optical computers.
A paper describing the research shows up in the journal Science.
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