Playing Tricks with Light

Photonic materials--materials that interact strongly with light--may be the key to controlling and exploiting light in future optical devices. In analogy with the electronic band gap in insulators and semiconductors, materials with a photonic band gap can be constructed, with applications for example in novel optical fibers or lasers. Another type of photonic material exploits the surface properties of materials with a negative dielectric constant (such as most metals), which lead to nonlinear effects allowing the focusing of radiative energy in very small volumes. Future applications in light switching, another important aspect of optical technology, can be envisioned.