Source: wikibot/photonic-crystal
= Photonic crystal
{wiki=Photonic_crystal}
A photonic crystal is an optical material that has a periodic structure on the scale of the wavelength of light. This periodicity creates a photonic band gap, which is a range of wavelengths (or frequencies) over which light cannot propagate through the material. Just as a semiconductor crystal can control the flow of electrons, a photonic crystal can control the flow of photons (light).