The team, led by Professor Jeremy Baumberg and including researchers from Mexico and Greece, built a switch which uses a state of matter called a Polariton Bose-Einstein condensate. This allows electrical and optical signals to be mixed, while using miniscule amounts of energy.
Such condensates are generated by trapping light between mirrors spaced a few microns apart and letting it interact with thin pieces of semiconductor material. This creates a polariton – a half light, half matter mixture. When a lot of polaritons are in the same space, condensation can take place and a light-matter fluid formed which spins either clockwise or anticlockwise. By applying an electric field to this system, the researchers controlled the condensate’s spin and could switch it between the two states. The light emitted by the polariton can then be sent through optical fibres for communication.
According to Dr Alexander Dreismann from Cambridge’s Cavendish Laboratory: “The polariton switch unifies the best properties of electronics and optics into one tiny device that can deliver at very high speeds while using minimal amounts of power.”
“We have made a field effect light switch that can bridge the gap between optics and electronics,” said fellow researcher Dr Hamid Ohadi. “We’re reaching the limits of how small we can make transistors, and electronics based on liquid light could be a way of increasing the power and efficiency of the electronics we rely on.”