Patent ID: 7011925

Claim:
A three-dimensional memory apparatus for storing information in and retrieving information from a three-dimensional volume, comprising an active medium, which is capable of changing from a first to a second isomeric form as a response to radiation of a light beam having an energy substantially equal to a first threshold energy, wherein the concentration ratio between a first and a second isomeric form in any given volume portion represents a data unit; means for exposing said active medium to said light beam to induce a multiphoton absorption; said memory apparatus being characterized in that said active medium comprises a diarylalkene derivative of the general formula Ar 1 (R 1 )C═C(R 2 )Ar 2 , wherein Ar 1 and Ar 2 , which could be the same or different, are independently substituted or non-substituted aryl rings wherein the substituted groups have a strong absorption in the IR region; and R 1 and R 2 which are the same or different, are groups having strong absorption in the IR region; wherein said active medium is embedded in a three-dimensional supporting matrix; and further comprising means for reading a data unit stored within said given volume portion of said active medium embedded in said three-dimensional supporting matrix by measuring said concentration ratio between said first and second isomeric forms.