Holographic data storage systems

Other dye-based technologies evaluated for optical data storage include photo-chromic dyes for rewritable systems and azo dyes for holographic data storage. Spirobenzothiopyran dyes such as (40) absorb in the red/near-IR in their colored form and are suitable for erasible optical data storage [34]. Dyes for holographic data storage, such as (41), are similar to those used in nonlinear optics [35] (see below). 

Polymer-based photochromic systems have been studied extensively and are attractive in terms of practical applications because of their advantages of stability and processability. A number of reviews and articles dealing with various aspects of photochromic polymers and photoactive biomaterials have been published. 68 Chiral photochromic peptides are discussed in Chapter 13, and photochromic liquid crystals and polymers for holographic data storage and nonlinear optics have been reviewed. 69 Specific stereochemical effects in chiral photoresponsive polymers include ... 

Material science can also benefit from oligomeric state of proteins. New retinal nano-ceramic materials with pillared hybrid micro-structures were fabricated for potential applications in optical holographic data storage. It was observed that the Schiff bases in retinal have substantial effect on optical properties of nano-ceramic films as well as diffraction efficiency for holographic storage. This study indicates feasibility of optimizing optical properties of nano-ceramic clay systems using Schiff bases for a variety of photonic applications.40... 

CUR 10] Curtis K., Dhar L., Murphy L. et al., Future Developments, in Holographic Data Storage From Theory to Practical Systems, Wiley, Chichester, UK, 2010. 

The idea for holographic data storage arose in the early 1960s, but its commercial introduction has been a slow process. Despite the advances in systems design and materials, mainstream storage technologies have evolved... 

Nowadays most colorants have the purpose to satisfy our aesthetical needs and, thus, thousands of dyes and pigments are produced on industrial scales. Nevertheless, nearly periodically new demands arise for so-called fimctional dyes whose tt-conjugated systems exhibit novel functionahties beyond aesthetical purposes. Optical brighteners or near-infrared absorbers are examples where even transparency in the visible spectrum is desired and dyes for nonlinear optics, holographic optical data storage and two photon absorption are further examples where the color properties of dyes are insignificantly related to the functional demands. 

The potentially unique optical properties are due to azoaromatic chromophores containing side chain polymers [38—43]. These polymers are used as in micro- and nanotechnology based advance systems like optical based data storage [44], NLO materials [45, 46], holographic based memories [47], chiroptical based switches [48], surface relief based gratings [49-51], etc. The chemical stractures with variation of different side chains of the investigated azoaromatic polymers and copolymers are shown in Fig. 5. 

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