29-06-2010, 01:00 AM
ABSTRACT
The growth in demand for digital storage capacity exceeds 60% per annum. Facilities such as storage area networks, data warehouses, supercomputers and e-commerce, e- related data mining, require ever greater capacity in order to handle the volume of data to be processed. In addition, with the advent of high bandwidth Internet and data-intensive applications such as high-definition TV (HDTV) and video and music on-demand, even smaller devices such as personal VCRs, PDAs, mobile phones, etc.,. Future increases in density are possible by taking advantage of shorter wavelength lasers, higher lens numerical aperture (NA), or by employing near-field techniques. Finally, optical data storage capacities have been increased by creating double-sided media. Another approach to increasing the effective storage capacity is quite unique for optical memory technologies. Fluorescent multilayer disc (FMD) used for large amount of data storage. This is three-dimensional storage. True three-dimensional optical storage opens up another dimension in which to increase the capacity of a given volume of media, with the objective of achieving a cubic storage element having the dimensions of the writing /reading laser wavelength. Even with current wavelengths of 650 µm, this should suffice to store up to a Terabytes of data.
