An unnerving illusion that does not require props
 

The dream of “invisibility” has probably moved a step closer after US scientists announce they have crafted a material that can bend visible light around objects.

Researchers at the University of California at Berkeley, whose work is funded primarily by the Pentagon, have engineered materials that can control the direction of light.

The technology could lead to systems for rendering anything from people to large objects, such as aircraft or ships, invisible to the naked eye. Its application in the world of espionage and intelligence gathering are obvious. In 2006, John Pendry of Imperial College London and David Smith of Duke University in North Carolina used microwaves to achieve similar results, yet according to academics, achieving this effect using light is a significant advance.

Above and below - Tachi's projection project

Lead scientist on the light project Xiang Zhang said: “In the case of invisibility cloaks or shields, the material would need to curve light waves completely around the object like a flowing river around a rock.”

 

HOLY GRAIL OF ILLUSION ARTISTS

The search for “adaptive camouflage” as some researchers refer to invisibility, has a long history. In 1897, science fiction writer and author of The Invisible Man, H G Wells, introduced the idea, then fictional, of a scientific route to invisibility through bleach and mysterious rays.

Some would say today’s more modern experiments with visual stealth have their roots in a 1943 US Navy project code-named Yehudi. The purpose of this programme, which was highly secret at the time and came to light only in the 1980s, was to give Navy patrol aircraft a better chance of sinking enemy submarines. During 1942, German U-boats were a constant menace of the eastern seaboard of the United States and across the Atlantic. Hundreds of merchant vessels were sunk. Though torpedo firing aircraft were sent to sink the U-boats, they were often spotted long before they arrived and the submarines simply dived to safety.

The Yehudi team needed a way to make the aircraft harder to see, and camouflage paint alone wouldn’t do the job. Regardless of what colour was used, the aeroplane could be seen against the sky. Scientists believed the only way to make them less visible was to actually make the aircraft brighter by fitting dozens of bright lights. At the time, this seemed illogical to some military commanders. 

 

Air Force Material Commander Gen Bruce Carlson conducts interviews with media during F-117 Nighthawk Farewell Ceremony at Wright Patterson Air Force Base

Nevertheless, engineers fitted a TBM-3D Avenger torpedo-bomber with 10 sealed-beam lights installed along the wings leading edges and the rim of the engine cowling. When the intensity of the lights was adjusted to match the sky, the Avenger blended into the background. Tests revealed that the Yehudi system lowered the visual acquisition range from 12 miles down to two.

The British too worked mirrors, lights and other systems, but the art of illusion, though fairly successful in WWII and beyond, was never going to be a permanent solution.

 more.....