This work was funded by the National Natural Science Foundation of China, the National Minister of Education Program for Changjiang Scholars and Innovative Research Team in University, and the Hong Kong Central Allocation Fund. "With the anti-cloak, Potter can see outside if he wants to," says Chen, who conducted the research together with his colleagues at Shanghai Jiao Tong University and The Hong Kong University of Science and Technology. This would allow an invisible observer to see the outside by pressing a layer of anti-cloak material in contact with an invisibility cloak. While an invisibility cloak would bend light around an object, any region that came into contact with the anti-cloak would guide some light back so that it became visible. (In technical jargon, an anti-cloak would be anisotropic negative refractive index material that is impedance matched to the positive refractive index of the invisibility cloak). Their "anti-cloak" would be a material with optical properties perfectly matched to those of an invisibility cloak. Discover short videos related to invisible blanket harry potter on TikTok. In other words, invisible people would also be blind-not exactly what Harry Potter had in mind.īut now, Chen and his colleagues have developed way to partially cancel the invisibility cloak's cloaking effect. With no light penetrating a perfect invisibility cloak, there would be no way for an invisible person to see outside. Nobody has found a way yet to make an object invisible to the broad range of wavelengths our eyes are attuned to seeing, says Chen, and doing so would be a challenge.Īn even greater problem for anyone who has aspirations to be concealed in public one day is that invisibility achieved through transformation media is a two-way street. It works, but only for a narrow band of light wavelengths. Invisibility as it has been achieved so far in the laboratory is very limited. In 2006, scientists at Duke University demonstrated in the laboratory that an object made of metamaterial is partially invisible when viewed using microwaves. Transformation media cloaks are special materials that can bend light so much that it actually passes around the object completely. We perceive color, for instance, because different materials and coatings interact with light differently. All materials scatter, bounce, absorb, reflect and otherwise alter light rays that strike them. These materials are effectively invisible because of the way they interact with light. In recent years, however, scientists using special types of "meta" materials have shown that these Hollywood fantasies could one day become reality after all. From the 1933 classic The Invisible Man to the more recent installment in the Harry Potter series, devices that achieve invisibility have long been the stuff of film fantasy. If this sounds like more movie magic, it's no accident. He and his colleagues have proposed a theoretical "anti-cloak" that would partially cancel the effect of the invisibility cloak, which is another important problem as it turns out. "Cloaking is an important problem since invisibility can help survival in hostile environment," says Huanyang Chen of Shanghai Jiao Tong University in China.
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