Optical data storage principles

This new optical data storage device is reported to be robust and nonvolatile. The response time for the write—read beam is in the subnanosecond range, and no refreshing is requked for long-term retention of trapped charges (95). The basic principle may be appHed to other, similar photoconductive materials. 

Figure 10.9 Principles of optical data storage using near-infrared absorbers...

In order to show how polymer science makes an important contribution to optical data storage, it is necessary to explore some of its basic principles. 

Phase Change Materials (PCMs) are nowadays widely used for data recording and increasingly present non-volatile memories [1, 2]. Since Ovshinsky s precursor work [3], PCMs have been studied extensively, both experimentally [4-6] or with ab initio calculations [7-11], The operating principle of PCMs is based on the easy and reversible switching between the crystalline (C) and amorphous (A) states, each phase possessing very different electrical and optical properties. These materials are nowadays found in commercial applications for optical information storage and dissemination, such as CD-RW, DVD-RW or Blue-Ray disk, and could be used for the achievement of PC-RAM. 

The occurrence of transfer and amplihcation of chiral information could be particularly relevant for solid polymer hlms, since they could have, in principle, applications in chiro-optical devices and data storage systems. Recently, it has been reported that non-racemic SPS hlms, exhibiting the nanoporous 5 phase, are able to detect, amplify, and memorize the chirality of several volatile organic molecules [191,192]. 

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