"Electromagnetic Wormhole" May Make Us Invisible

It is humankind's never-dying dream, from the oldest myths to SF movies. Now, could the "electromagnetic wormhole" make us invisible? A team led by Allan Greenleaf of the University of Rochester has investigated a way to achieve this. The result would not be the classical wormhole, a theoretical bend in space and time acting like a shortcut, moving an object over vast distances.

"Instead, once something entered one end of the newly theorized tunnel, the object would be electromagnetically invisible to outside observation until it emerged from the other side. It would create a complete a disconnection between the outside world and stuff inside the cloaking region. It's good for hiding things.", said Greenleaf.

The tunnel would be based on a coat of metamaterials with a special ability of reflecting light, so that objects might become invisible. In October 2006, a Duke University team led by David R. Smith made a shield of metamaterials around 5 inches (13 cm) wide that could become invisible. But that shield functioned just in two dimensions and at a specific microwave frequencies, out of the visible spectrum.

The Rochester team noticed the similarities to their own mathematical computations. The researchers focused on building an object that would impede inquirers from seeing its whole content. This extended Duke's cloaking model into 3-D. "Geometrically, it's more complicated than a cloaking structure", said Greenleaf.

The new device resembles a door handle, being made of 2 spheres of metamaterials stuck onto each end of a metamaterial-coated tube. "The only way waves could get into the tunnel would be from either end. Although the size of the cylinder would be unlimited, the exact range of frequencies it could render invisible depends on what kind of metamaterials scientists end up developing. Still, even with limited frequencies, such a design would be useful for many applications", said Greenleaf.

The tunnel could eliminate the powerful distorting magnetic fields induced by some surgical instruments during operations.