Metamaterials are the key to perfect lenses, 'invisibility' cloaks and slow and stored broadband light. A three-dimensional optical metamaterial with a negative refractive index has now been created. Picture a straw in a glass of water. Looking at the glass from the side, the straw seems to break at the water surface and continue inside the liquid slightly shifted to one side and slightly wider than in the air. The difference between the optical density' of water and air, which is responsible for this phenomenon, is usually expressed in terms of the materials' refractive indices - that of water is higher than that of air.
展开▼
