Controlling light’s path could enable invisibility or harness an intriguing but so far elusive stretch of the spectrum
Light is a nimble gymnast. It travels in many colors and frequencies. Its waves, whether long or short, can shift to be longer or shorter. Light waves change direction. They bounce.
What light can’t do, on its own at least, is bend backward. In other words, it always refracts or reflects in a predictable, normal direction.
Scientists seeking to make light waves do such unnatural gymnastics have failed to find any natural material that does the job. But in recent years, physicists and engineers have been experimenting with different “metamaterials,” engineered substances that interact with electromagnetic waves in precisely controlled ways. The researchers have made swift progress: Already, they have created metamaterials that can in fact bend light backward. By reversing refraction, these new materials could essentially take a fish out of water, making it appear to float above the water’s surface. Theoretically, the materials also can, just like