Information Stored into Slowed Laser Light

The scientists slowed the laser light pulse from 300,000 kilometers per second to just several hundred meters per second, allowing them to capture the pulse for about a second.
"What we've done here is create a quantum memory," said Dr. Matthew Sellars of the Laser Physics Centre at the Australian National University in Canberra, Australia.
Slowing down light allows scientists to map information onto it. The information is then transferred from the light to the crystal, Sellars said. Then when the scientists release the light, the information is transferred back onto the beam.
"Digital information can be expressed with pulses of light," Sellars said. "If we can store the light pulses for a very long time, we have a memory that operates on a quantum scale."
To slow down the light, the researchers used a silicate crystal doped with a rare-earth element called praseodymium. Laser light pulses fired at the crystal are normally absorbed and don't pass through, Sellars said. But when a secondary laser was directed at the crystal, it became transparent, allowing light from the first laser to move through.