Forget the imaginary filaments used to weave the clothes that fooled the fabled emperor, can we make real invisible threads instead? Combining techniques used to produce light-bending metamaterials with those used to make optical fibres might just do the trick.
Alessandro Tuniz at the University of Sydney's Institute of Photonics and Optical Science in Australia is one of many physicists interested in the optical metamaterials that are being fashioned into "invisibility cloaks" in labs across the world. These metamaterials incorporate components much smaller than the wavelength of light, which allows them to control the light waves and gives them optical properties beyond those of conventional materials.
However, as physicists have discovered, fabricating metamaterials using components small enough to manipulate the sub-micrometre wavelengths of visible light is no mean feat. To avoid that problem, Tuniz's colleagues Boris Kuhlmey, Simon Fleming and Maryanne Large have suggested an elegant way to shrink a larger metamaterial-like structure down to a size capable of controlling visible light: assemble standard glass rods and metal tubes into a cylinder, heat the assembly until it softens, and draw it into a long thin fibre. The process preserves the shapes of internal structures, but shrinks them down to the nanoscale needed to control visible light, and the resultant metamaterial is in the form of a thread that is thin enough to be flexible, like an optical fibre. So far, Tuniz and colleagues have produced 10-micrometre-thick threads.
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