When nature can’t supply raw ingredients for next-generation hardware, scientists create their own. Man-made “metamaterials” are going beyond the lab and into real-world applications. Scientists use existing composite materials, like the gold and gallium-arsenide mixes used in electronics, to create complex, though tiny, structures. These When nature can’t supply raw ingredients for next-generation hardware, scientists create their own. Man-made “metamaterials” are going beyond the lab and into real-world applications. Scientists use existing composite materials, like the gold and gallium-arsenide mixes used in electronics, to create complex, though tiny, structures. These nano-size bumps, crosses, holes or ridges manipulate electromagnetic waves that hit them. Early prototypes of invisibility cloaks, which would guide light around an object to be shielded, have generated some techno­buzz. But researchers have quietly been inventing more near-term materials that will soon appear in the pockets of consumers and in the hands of military users.