Technology research: Cloaking device could render objects invisible

Posted by Wolfgang Gruener

West Lafayette (IN) – Researchers at Purdue University claim to have developed the concept of a device that that can render objects invisible in a single visible wavelength.

Developing approaches to make solid materials invisible or at least transparent appears to be gaining traction these days and if we believe an announcement from Purdue announcement today, hiding objects from uninvited eyes may get a whole lot easier sometime in the future.

Researchers said they have developed a “cloaking” device that can guide light around anything placed inside its “cloak” and even allow viewers to see what is directly behind the object. The device, so far only existent as a theoretical design, that uses cylindrical array of nano-needles radiating outward from a central spoke. The cloak, which is said to look like a round hairbrush, bends light around a covered object.

Wenshan Cai, a member of the research group at Purdue University, told TG Daily that there are no plans to actually build a cloaking device due to technical limitations. While he said it would be possible to build cloaking devices based on the design in a micron-range, larger cloaks that would surround centimeter-sized objects, cannot be built today. However, Cai believes that based on the group’s simulations, the cloaking device would actually work.  

Also, a major limitation of the concept it works only for any single wavelength, and not for the entire frequency range of the visible spectrum. The current design works in a wavelength of 632.8 nanometers, which translates to the color red. The researchers believe that their design is a first step that could lead the way to “creating an optical cloaking device that might work for all wavelengths of visible light.”