New ‘light transistor’ for optical circuits

A gadget that boosts a laser signal by a factor of 60 - based on the transfer of photons rather than electrons - could seed a new generation of ultrafast components for optical circuits. Junji Tominaga of the National Institute of Advanced Industrial Science in Japan and colleagues developed the device, which paves the way for all-optical circuits that transmit information at - literally - the speed of light. (J Tominaga et al 2001 Appl. Phys. Lett. 78 2417). The new 'photonic transistor' would be just nanometres thick, unlike existing devices that rely on long optical fibres to produce the gain.