A new type of active "invisible cloak" that allows objects to deceive monitor cameras has been developed by scientists at northwest China's Lanzhou University, Guangming Daily reported.

Imagine an armored vehicle that, with the help of the newly developed invisible cloak, passes before a monitor camera and on the screen an ox cart appears or perhaps even nothing at all! This may still sound fictional at present, but could become reality in the not-too-distant future.

Prof. Mei Zhonglei, head of the program research group, said that the design of active invisible cloaking had been based on the Laplace's Equation, a technology that can conceal or disguise an object in order to realize a dynamic control. A report on the achievement has been published in Physical Review Letters, one of the most prestigious journals in the field of physics compiled by the American Physical Society.

Mei explained that the detection instruments are usually able to register objects because they block those electromagnetic waves the former emits. In the area of invisibility, there are numerous frequency bands ranging from microwaves and infra-red rays, to visible light.

"Our experiment has realized the camouflaging of the direct current (DC) field. The whole process is just like the water of a mountain stream that bypasses the stones it encounters and goes on as if they were not there."

The cloak can achieve a dynamic control of objects by adjusting the active equipment, said Mei. "Suppose you use this equipment underground. You could, for example, screen a secret fuel depot or buried treasure so that they can appear to be other objects when scanned from the Earth's surface, thus realizing an active camouflage control."

The invisible cloak is actually a circuit board of concentric circles made up by connected resistors. The center of the circle is connected to 36 braid-like signal sources. Different from previous invisibility equipment requiring complicated artificial electromagnetic materials, the new system is simply created through the welding of common ordinary electronic components.

Mei predicted that the technique carries important theoretical value and practical significance. "This is the first time that active invisibility technology has been verified by scientific experiment. Its success has further enriched the theory of invisibility, laying a foundation for the future design of more flexible invisibility equipment."

Electromagnetic invisible cloaking can be widely applied to the realms of national defense, earth resource exploration, underground/underwater research, target hiding and camouflage, he added.

Currently, invisible cloaking can only aim at objects of a specific frequency, small volume and comparatively static state, and is thus still be far from perfection. For some time, scientists have been seeking mobile invisibility through the use of multi-frequency bands.

It is worth mentioning that the first author of the paper was Ma Qian, a 2011 graduate of the School of Information Science and Engineering of Lanzhou University, majoring in communications engineering.

Go to Forum >>0 Comment(s)