Add to ORKGThe last decades of the twentieth century can be characterized as a period in which the use of computers for information storage has integrated in all parts of society. The continuously increasing amount of data to be stored and manipulated has urged the need for high speed computers and large storage capacities. One of the most important challenges in this field is the development of materials and techniques to place as much data as possible on the least amount of material. The ultimate goal would be to achieve information storage at the molecular or even at the atomic level;1 processing of data should occur close to the speed of light by the use of alloptical switching devices