Light storage

Holographic data storage is looking promising apart from one little problem:
reading the data tends to erase it. Now researchers at Caltech in Pasadena have
proposed a solution using a two-colour approach. They dope the holographic
crystal with iron and manganese to create two deep electron “traps”. This allows
ultraviolet light to store data as an interference pattern which can be read by
red light. UV is also used to erase the data. The research is published in the
current edition of Nature (vol 393, p 665).