A Harvard research team has conducted research based on the properties of Bose-Einstein condensate, which could lead to advances in computing and optical communication. The team was able to pass a pulse of light through a cloud of sodium atoms, capture it, and then made the light reappear in a second cloud of sodium atoms.  They were able to turn the light into matter.

They applied the brakes by shining light into a cloud of sodium atoms trapped in a vacuum and cooled to just above absolute zero (-273 Celsius), the theoretical state of zero heat.

At this temperature the atoms coalesce to form a Bose-Einstein condensate, an exotic quantum entity first predicted by Albert Einstein and created in the lab in 1995.

A second laser tuned the tiny atomic cloud to slow the pulse of light.

In 2001, working with a team from the Harvard Smithsonian Center for Astrophysics, the same group brought light to a halt, by slowly turning off the second control laser.

Switching the laser back on set the light free.

The new experiment builds on this work.

Instead of just one cloud of sodium atoms, the new setup used two, a fraction of a millimetre apart.

"The two atom clouds were separated and had never seen each other before," said Professor Hau.

A pulse of light was shone on the first cloud, impressing a "cast" of the pulse into a clump of spinning sodium atoms, nudged in the direction of the second condensate.

This slowly-moving clump was composed entirely of sodium atoms, effectively turning light into matter.

Once the "messenger" group had merged with the second cloud, a second laser was shone through the condensate to revive the original pulse of light.

From a standing start, the reconstructed beam sped back up to the normal speed of light. Analysis showed that it possessed exactly the same shape and wavelength of the original beam, although it was slightly weaker.