Multidimensional optical data storage

The concept of optical data storage is based on the use of a laser beam that is focused onto a recording material to produce a spot where physical or chemical properties of the material are changed. The first generation of the optical data storage devices is the two-dimensional (2-D) devices such as compact disks (CDs) and single layer digital video disc (DVDs) with a 2-D storage density of up to 0.8 Gbits/cm2 for a visible laser beam. The idea of using the third spatial dimension has led to the generation of multi-layered DVDs with capacity of up to 100 Gigabytes per disk.