Storing Data on a Laser in a Crystal

Back in October of 2005 I read an article on wired.com which stated that scientists have discovered a way to store data encoded onto a laser in a crystal. The article was removed and is not available in their archive, but I was able to find the cached version via Google. The article is back online here.

The laser is slowed down using a silicate crystal doped with a rare-earth element - slow enough to map data onto the laser using photons, which is then stored in a crystal for later retrieval. The laser would normally be absorbed and not pass through the crystal, but when shining a secondary laser at the crystal it becomes transparent, making way for the first laser with the data. When the laser with data enters the crystal, the secondary laser is turned off which traps the first laser inside. When the secondary laser is then turned on again, the first laser (with data) is released.

What I want to know is how these scientists came up with the original concept.