Light switch at the speed of light

摘要

Optical devices promise to be faster than their electronic counterparts, but to achieve this, swifter switches are needed to route the flow of information encoded by light. Georgios Ctistis and Willem Vos at the University of Twente in the Netherlands and their colleagues have built a switch that changes from off to on to off in just one-trillionth of a second. They used a laser beam to change the refractive index of a microcavity made from gallium arsenide and aluminium arsenide layers, thereby switching the wavelength of light the cavity transmits most readily.