A nanostructured array of holes used as an optical semiconductor.

Just as electronic bandgaps (energy difference between a non-conductive state and the conductive state) prevent electrons from passing through, photonic crystals create photonic bandgaps that confine light.

This technology increases the efficiency in optical fibers and allows microscopic lasers to be built. It is also expected to be used in the construction of photonic circuits that can stand alone or be integrated into semiconductor circuits.