Optical data storage future

Table 9 compares the most important properties of substrate materials based on BPA-PC, PMMA, and CPO (three different products) (216,217). The future will prove if the current disadvantages of CPO against BPA-PC regarding warp, processibiUty (melt viscosity), and especially cost can be alleviated. CycHc polyolefins (CPO) and, especially cycloolefin copolymers (COC) (218) and blends of cycloolefin copolymers with suitable engineering plastics have the potential to be interesting materials for substrate disks for optical data storage. 

M. Ohtsu, Nanophotonics and application to future storage technology. Technical Digest, The Joint International Symposium on Optical Memory and Optical Data Storage 2008, aSOM/ODS 08), HI, USA, pp. 24-26 (paper number MAOl TD0501), 13-17 July 2008... 

With the further development of new photo-erasable materials and advances in polymer film base technology a successful future for optical data storage seems assured. 

With regard to the future, nanoimprint lithography is still considered as a next generation Uthography technique in microelectronics, but it wiD most probably remain a generic technique for specific applications with special processes and tools in the fields of optics, data storage [115], and applications requiring 3D fabrication or... 

Photopolymers are used today to make holograms. In the near future, volume holograms in multilayer materials will lead to optical data storage of unprecedented storage capacity. 

Liquid crystal polymers are also used in electrooptic displays. Side-chain polymers are quite suitable for this purpose, but usually involve much larger elastic and viscous constants, which slow the response of the device (33). The chiral smectic C phase is perhaps best suited for a polymer field effect device. The abiHty to attach dichroic or fluorescent dyes as a proportion of the side groups opens the door to appHcations not easily achieved with low molecular weight Hquid crystals. Polymers with smectic phases have also been used to create laser writable devices (30). The laser can address areas a few micrometers wide, changing a clear state to a strong scattering state or vice versa. Future uses of Hquid crystal polymers may include data storage devices. Polymers with nonlinear optical properties may also become important for device appHcations. 

High quantum yield photochemical reactions of condensed-phase species may become useful for future optical applications such as molecular switches, optical limiters, and read-write data storage media. Toward these ends, much research has been conducted on novel nonlinear chemical-based materials such as conducting polymers and metal-organic species. Monitoring the early time-dependent processes of these photochemical reactions is key to understanding the fundamental mechanisms and rates that control the outcome of these reactions, and this could lead to improved speed and efficiencies of devices. 

Despite minor drawbacks, optical data techniques are the technology of the future for data storage. The potential for great strides forward in performance clearly exists. 

Intense research in the field of metal nanoparticles by chemists, physicists, and materials scientists is motivated by the search for new materials that hold novel physical (electronic, magnetic, optical) and chemical (catalytic) properties. Recently, the research on monometallic nanoparticles has been carried out in order to further miniaturize electronic devices [26-28] as well as to elucidate the fundamental question of how electronic properties of molecular aggregates evolve into novel properties with increasing size in this intermediate region between a molecule and a bulk [3,29-33]. Possible future applications include the areas of ultrafast communication and a large quantity of data storage [3,31,32,34]. 

---