A flat lens made of paint whitener on a sliver of glass could revolutionise optics, according to its US inventors. Just 2mm across and finer than a human hair, the tiny device can magnify nanoscale objects and gives a sharper focus than top-end microscope lenses. It is the latest example of the power of metamaterials, whose novel properties emerge from their structure. Shapes on the surface of this lens are smaller than the wavelength of light involved: a thousandth of a millimetre.