Photo Gallery The Dream of Invisibility
Optical Illusion: An invisibility device tricks the viewer into thinking that a light ray passes directly through an object, rather than being deflected.
In reality, the invisibility device makes the light beam circle around the object.
Until now, invisibility devices have only worked for objects in two dimensions, but now a pair of researchers have performed calculations that should allow for a device that works with objects in three dimensions.
With the help of meta-materials, which bend light and magnetic fields around an object, an invisible sphere is possible. When the light beam (yellow) hits the invisibility device, it is deflected and travels around the object. This makes it appear as if the sphere is invisible.
This figure shows how light could get bent by an invisibility device attached to an object in three dimensions.
The light experiments can get quite complex. According to the researchers' calculations, a lens-shaped object like the one pictured here could send light curving around both ends of it if covered with an invisibility device.
Scientists have already tried experiments which make objects deflect water waves.
Here you can see how a water-based cloak of invisibility deflects waves around the object.
About two years ago scientists in the United States built a two-dimenstional invisibility device. The ring was made out of several rows of copper wire and glass filaments that deflected microwaves.
This graphic shows how meta-materials deflect the electromagnetic radiation around the ring. Viewers have the impression that the ring doesn't exist at all.
An example of the meta-material essential for a cloak of invisibility. It is made of layers of silver that are 30 nanometers wide and layers of magnesium fluoride that are 50 nanometers wide. The materials form a prism that in turn creates an invisibility device.
