'Predator'-Proof: An Invisibility Cloak for Heat
Thermal invisibility cloak: Heat is passed around the central area from the left to the right. Temperature characteristics (white lines) remain parallel.
CREDIT: R. Schittny/KIT
A new invisibility cloak for heat could help protect electronics against dangerous heat spikes, researchers say.
In the past decade, scientists have invented special materials that can route light and sound around objects. These make items they cover appear as if they are not there, recalling the cloaks of invisibility in "Harry Potter" and "Star Trek."
Now a team of researchers from Germany and France has developed a cloak that can guide the flow of heat around objects, making them thermally invisible.
"We manufactured a working cloaking device for heat flow for the first time," Robert Schittny, a physicist at the Karlsruhe Institute of Technology in Germany, told TechNewsDaily.
The scientists created the cloak by cutting hexagonal arrays of microscopic holes in a copper plate. They then filled these holes with a thin layer of silicone rubber. [Read also: 'Invisibility Cloak' Renders Objects Hidden to the Naked Eye]
The thermal invisibility cloak is an example of a so-called metamaterial, a class of manmade materials whose properties derive as much from how they are arranged as from what they are made of.
"For the thermal invisibility cloak, both materials have to be arranged smartly," Schittny said.
Researchers placed one end of the copper plate in hot water and dipped the other in room-temperature water. Heat naturally flowed across the plate from hot to cold.
However, the design of the plate forced heat to flow around the center as if it were not there. An infrared camera revealed that heat migrated around a copper disc in the middle of this structure, confirming that the cloak kept the disc from warming.
"There might be applications anywhere where specific and well-defined heat management is needed, be it on the microscopic — for example, microelectronics — or macroscopic scale," Schittny said.
So far, this cloak only controls heat in two dimensions. However, it would be possible to create 3-D heat cloaks, i.e. those that could encapsulate objects, Schittny said.
The scientist and his colleagues detailed their findings May 10 in the journal Physical Review Letters.