Institution: Imperial College | Sign In as Individual | FAQ Also see the archival list of Science's Compass: Enhanced Perspectives APPLIED PHYSICS: Enhanced: Playing Tricks with Light

The notion that altering the structure of a material can profoundly alter its electromagnetic properties has led to concepts such as the photonic insulator, enabling new technologies that offer control over light not previously thought possible. These new materials, often referred to somewhat imprecisely as "photonic materials, " have in common the property of strong interaction with light. Yablonovitch [HN1] (1) and John [HN2] (2) first pointed out the importance of structure for electromagnetic properties by drawing analogies between light and electrons. Both have a wave-like nature and can therefore be diffracted. We are accustomed to electronic behavior being dictated by the diffraction of electrons from the periodic potential of an atomic lattice. In a normal metal, it is possible to excite the electrons by giving them a small amount of energy to set them in motion, whereas this is forbidden for insulators because of a gap in energy right above the occupied electronic levels [HN3]. This gap arises from the diffractiv