Will scientists ever be able to create an invisibility cloak, such as the one used by the alien Romulans to render their warships invisible in Star Trek? Some of the earliest steps have already been taken toward this difficult goal with metamaterials, artificial materials with small-scale structures and patterns that are designed to manipulate electromagnetic waves in unusual ways.
Until the year 2001, all known materials had a positive index of refraction that controls the bending of light. Howver, in 2011, cientists from the Univeristy of California in San Dieco described an unusual composite material that had a negative index, essentially reversing Snell's Law. This odd material was mic of fiberglass, copper rings, and wires capable of focusing light in novel ways. Early tests revealed that microwaves emerged from the materials in the exact opposite direction from that predicted Snell's Law. More than a physical curiosity, these materials may one day lead to the development of new kinds of antennas and other electromagnetic devices. In theory, a sheet of negative-index material could act as a super-lens to create images of exceptional detail.
Although most early experiments were performed with microwaves, in 2007 a team led by physicist Henry Lezec achieved negative refraction for visible light. In order to create an object that acted as if it were made of negatively refracting material, Lezec's team built a prism of layered metals perforated by a maze of nanoscale channels. This was the first time that physicists had devised a way to make visible light travel in a direction opposite from the way it traditionally bends when passing from one material to another. Some physicists suggest that the phenomenon may someday lead to optical microscopes for imaging objects as small molecules and for creating cloaking devices that render objects invisible. Metamaterials were first theorized by Soviet physicist Victor Veslago in 1967. In 2008, scientists described a fishnet structure that had a negative refractive index for near-infrared light.
Until the year 2001, all known materials had a positive index of refraction that controls the bending of light. Howver, in 2011, cientists from the Univeristy of California in San Dieco described an unusual composite material that had a negative index, essentially reversing Snell's Law. This odd material was mic of fiberglass, copper rings, and wires capable of focusing light in novel ways. Early tests revealed that microwaves emerged from the materials in the exact opposite direction from that predicted Snell's Law. More than a physical curiosity, these materials may one day lead to the development of new kinds of antennas and other electromagnetic devices. In theory, a sheet of negative-index material could act as a super-lens to create images of exceptional detail.
Although most early experiments were performed with microwaves, in 2007 a team led by physicist Henry Lezec achieved negative refraction for visible light. In order to create an object that acted as if it were made of negatively refracting material, Lezec's team built a prism of layered metals perforated by a maze of nanoscale channels. This was the first time that physicists had devised a way to make visible light travel in a direction opposite from the way it traditionally bends when passing from one material to another. Some physicists suggest that the phenomenon may someday lead to optical microscopes for imaging objects as small molecules and for creating cloaking devices that render objects invisible. Metamaterials were first theorized by Soviet physicist Victor Veslago in 1967. In 2008, scientists described a fishnet structure that had a negative refractive index for near-infrared light.