Blue storage capacity

As blue diode lasers became available on a large scale [10], a new generation of storage disks with further increased storage capacity was developed by the Blu-ray Disc Association and by Toshiba and NEC within the DVD Forum [4j. As can be seen in Table 12.1, a HD-DVD holds 15 GB and BDs hold 25 GB (singlelayer DB) or 50 GB (dual-layer BD). Figure 12.3 shows, as a typical example, the cross-section of a novel disk type having a triple-layer structure one BD layer and a dual DVD layer to be read by a blue and a red laser, respectively. 

FIGURE 3-11 A patent is good for 17 years. This is a facsimile of the patent awarded to S. Nakamura, whose work with blue lasers increased the storage capacity of optical disks. 

Fig. 22.11 Top gas temperature before SCR catalyst versus time. Bottom actual NH3 load red line), ideal loading range (green area), and NH3 storage capacity (blue line). WHTC hot, Fe-Cu catalyst combination...

Fig. 3.3 Cyclic voltammetry diagram for iridium oxide, the blue area is the so called cathodic charge storage capacity (CSCc), original picture was taken from [1], with permission...

Frequency doubling, or SHG, as illustrated in Figure 1, is of keen interest as a means of generating new laser sources. Frequency doubling of low power diode lasers from the red or infrared into the blue comprise a prime commercial application. Device outlets include higher capacity optical storage devices, as well as more sensitive laser printers and copiers. The objective is to increase not only the molecular response p, but of course the material response Be-... 

Blu-ray An optical disk format. Developed by a consortium of over 180 companies led by Sony, Blu-ray disks are intended to supersede the DVD both for the distribution of video and for data storage - they can hold up to 25 Gb on each ot up to two layers. Blu-ray achieves this greater capacity by using a blue (actually, a violet) laser rather than the red laser used for DVDs the shorter wavelength allows the beam to be focused more precisely and so more data to be packed into a given space. Currently (2009) some high-deflnition DVDs have been released in Blu-ray format, and computer Blu-ray drives are becoming available. 

The SHG finds application in the development of new optical information storage systems where near-infrared laser light can be converted into deep-blue light. The capacity for storage information on optical discs rises strongly by frequency doubling (Prasad and Williams, 1991). 

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