It may an illusion but scientists are close to creating a way which will make humans and objects invisible to the eye.

Researchers at the University of California at Berkeley have engineered a material that can control visible light's direction of travel -- bending it around objects to render anything from people to large objects like ships and tanks invisible.

According to the scientists, by bending visible light around an object will help to hide it.

"In the case of invisibility cloaks or shields, the material would need to curve light waves completely around the object like a river flowing around a rock," lead researcher Xiang Zhang was quoted by 'The Sunday Times' as saying.

An observer looking at the cloaked object would then see light from behind it -- making it seem to disappear. Substances capable of achieving such feats are known as "meta-materials" and have power to "grab" electromagnetic radiation and deflect it smoothly, according to the scientists led by California University.

In fact, they engineered the material's elements to within about 0.00000066 of a metre as no such material occurs naturally and it is only in the past few years that nano-scale engineering has advanced sufficiently.

Their work followed an earlier work at Imperial College London that achieved similar results with microwaves.

Like light, these are a form of electromagnetic radiation but their longer wave-length makes them far easier to manipulate. Achieving the same effect with visible light is a big advance, the researchers said.