A new optical switch sets a record for minimal power use, making it a good candidate for nanophotonic circuitry, according to its creators. The silicon-based photonic crystal nanocavity (PCN) has a Q factor of 500,000. It was developed by a team of researchers from the Federal Polytechnic University of Lausanne (EPFL). the nanocavity acts as a switch, allowing or blocking the flow of light, similar to an electronic transistor. A tiny amount of incoming light is enough to cause a small change in the wavelength of the light trapped inside the cavity; this optical bi-stability is what makes the optical cavity act like a switch. “In this work we have achieved nonlinear effects at a record low intensity of light,” said professor Dr. Romuald Houdre. “Our structure is also one of the smallest ever designed to show such record nonlinear properties, and it may be built using standard nanofabrication technology.” The research was published in Applied Physics Letters (doi: 10.1063/1.4894441). For more information, visit www.epfl.ch.