It isn’t apparent to everyone, but there’s a lot more to invisibility than meets the eye.
Most manifestations of invisibility are based on optical illusion, says theoretical physicist Ulf Leonhardt (below, comfy in an invisible chair). True invisibility, he contends, can be achieved only with metamaterials, engineered substances with a property—in this case the ability to bend light around themselves—not found in nature. “Invisibility is all about manipulating space,” he says, and “bending light means manipulating the geometry of space.” Unfortunately optical metamaterials don’t just appear out of thin air, and they are costly to manufacture. Plus, there’s no known material that can bend light in a thin layer around an object as large as a human.
Meanwhile, Leonhardt and his research team at the University of St. Andrews, in Scotland, are working on perfect imaging, the ability to see even the most minute objects with unlimited sharpness. Optical lenses max out at a resolution of about the wavelength of light, he says; smaller objects—some viruses, the interior components of cells, atoms, molecules—are beyond their range. Electron microscopes can see inside these structures, but cells must be killed in the process. Perfect imaging would allow views of the processes of life in living cells. The St. Andrews researchers have already demonstrated that this technology is possible. The next step, Leonhardt says, which could to be reached by year’s end, is to apply and demonstrate what they’ve proven in theory.
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