Photonic crystals offer a host of possibilities.

This article presents information on photonic crystals. The fertile concept of the photonic crystal is spawning a new generation of optical devices that confine light using internal microstructures. The best-known class of devices is fundamentally among the simplest--holey fibers--which are waveguides that confine light inside the fiber so it propagates in a single direction. Photonic crystals are materials in which internal microstructures create period variations in the dielectric constant on the scale of a wavelength of light.