Nanophotonics

Scientists have dreamed of building nanoscale devices that manipulate light the same way digital devices control electricity. Over the past decade, they have made impressive strides in reaching that goal. Today, there are nanoscale structures that scatter, refract, filter, slow, trap and otherwise manipulate light. Researchers have combined these structures to create nanophotonic counterparts of integrated circuits, as well as more efficient solar cells, ultra-small lasers and sensors, and more powerful optical microscopes. One of the key breakthroughs has been a growing ability to control light waves that measure in the hundreds of nanometers using structures measured in the tens of nanometers. Scientists once thought that it was impossible to manipulate light using such small assemblies. At the nanoscale, however, these structures interact with larger light waves in unusual ways. One approach takes advantage of plasmons, waves of electrons that absorb light as they roll across a metal's surface. Tapping electrons also makes it easier to convert light, which is faster and carries more information, into electrons, which are easier to process digitally. By integrating light sensors and nanoscale lasers into silicon chips, researchers hope to create faster circuits for computers and networks. Plasmons also make it possible to view fragile objects, such as DNA, proteins and polymers, through optical microscopes. Researchers are also investigating such nanophotonic devices as nanoscale lasers, quantum dots for solar cells and optical materials for quantum computing.