WASHINGTON, March 26In a new approach to invisibility cloaking, a team of French researchers has proposed isolating or cloaking objects from sources of heatessentially "thermal cloaking." This method, which the researchers describe in the Optical Society's (OSA) open-access journal Optics Express, taps into some of the same principles as optical cloaking and may lead to novel ways to control heat in electronics and, on an even larger scale, might someday prove useful for spacecraft and solar technologies.
Recent advances in invisibility cloaks are based on the physics of transformation optics, which involves metamaterials and bending light so that it propagates around a space rather than through it. Sebastien Guenneau, affiliated with both the University of Aix-Marseille and France's Centre National de la Recherche Scientifique (CRNS), decided to investigate, with CRNS colleagues, whether a similar approach might be possible for thermal diffusion.
"Our key goal with this research was to control the way heat diffuses in a manner similar to those that have already been achieved for waves, such as light waves or sound waves, by using the tools of transformation optics," says Guenneau.
Though this technology uses the same fundamental theories as recent advances in optical cloaking, there is a key difference. Until now, he explains, cloaking research has revolved around manipulating trajectories of waves. These include electromagnetic (light), pressure (sound), elastodynamic (seismic), and hydrodynamic (ocean) waves. The biggest difference in their study of heat, he points out, is that the physical phenomenon involved is diffusion, not wave propagation.
"Heat isn't a waveit simply diffuses from hot to cold regions," Guenneau says. "The mathematics and physics at play are much different. For instance, a wave can travel long distances with l
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