MIT researchers build an all-optical transistor

Optical computing—using light rather than electricity to perform calculations—could pay dividends for both conventional computers and quantum computers, largely hypothetical devices that could perform some types of computations exponentially faster than classical computers.

In the latest issue of the journal Science, researchers at MIT's Research Laboratory of Electronics—together with colleagues at Harvard University and the Vienna University of Technology—describe the experimental realization of an optical switch that's controlled by a single photon, allowing light to govern the transmission of light. As such, it's the optical analog of a transistor, the fundamental component of a computing circuit.

Moreover, since the weird, counterintuitive effects of quantum physics are easier to see in individual particles than in clusters of particles, the ability to use a single photon to flip the switch could make it useful for quantum computing.