From MIT News: “Single-photon transmitter could enable new quantum devices”

July 25, 2012
David L. Chandler

Long-sought goal for quantum devices — the ability to transmit single photons while blocking multiple photons — is finally achieved.

In theory, quantum computers should be able to perform certain kinds of complex calculations much faster than conventional computers, and quantum-based communication could be invulnerable to eavesdropping. But producing quantum components for real-world devices has proved to be fraught with daunting challenges.

An artist’s conception shows how any number of incoming photons (top) can be absorbed by a cloud of ultra-cold atoms (center), tuned so that only one single photon can pass through at a time. Being able to produce a controlled beam of single photons has been a goal of research toward creating quantum devices. Graphic: Christine Daniloff

Now, a team of researchers at MIT and Harvard University has achieved a crucial long-term goal of such efforts: the ability to convert a laser beam into a stream of single photons, or particles of light, in a controlled way. The successful demonstration of this achievement is detailed in a paper published this week in the journal Nature by MIT doctoral student Thibault Peyronel and colleagues.

See the full article here.