Data storage, holographic

Even with these limitations, holographic data storage using an all optical procedure is an attractive option since it offers the potential for storing terabytes of information with high transfer rates and short access times.  

Photorefractive polymers are also being developed for use in both permanent and real-time holography (see section 5.6.3). 

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Fig. 8. Holographic data storage experimental results photographs of holographic reconstmctions from a multiplexed hologram (51).

Photopolymers and photothermoplasts are mentioned only in connection with holographic data storage (see Holography). The classical method of optical data storage in silver haUde films (photographic film, microfiche technique) is not discussed (see Photography). 

To date most of the polymeric materials have demonstrated potential rather than acmal commercial applications. The two-beam coupling behaviour has obvious applications in real-time optical processing and holographic data storage. 

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 ... 

H. J. Coufal, D. Psaltis, and G. T. Sincerbox, Holographic Data Storage, Springer Series in Optical Sciences, 76, 2000. 

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... 

Wu PF, Bhamidipati M, Coles M, Rao D (2004) Biological nano-ceramic materials for holographic data storage. Chem. Phys. Lett. 400(4-6) 506-510... 

Berg et al. synthesized peptide oligomers that incorporated 4-cyanoazobenzene for erasable holographic data storage [168]. The oligomer is a diamino acid-N -substituted peptide (DNO) repeat unit, compound 4, with an azobenzene side chain... 

A major application of photorefractive polymers as holographic data storage media is a real possibility. In this application two interfering laser beams write a hologram... 

Hessehnk, L., Orlov, S.S., Liu, A., Akella, A., Lande, D., and Neurgaonkar, R.R., Photorefractive materials for nonvolatile volume holographic data storage, Science, 282, 1089, 1998. 

The ease of structural modification of fluorinated olefins makes them an interesting structural scaffold for design of functional materials such as liquid crystals [10, 20, 21], compounds for non-linear optics (NLO) [22], or media for holographic data storage [23] (Scheme 2.194). 

Scheme 2.194 Examples of the use of fluoroolefins as liquid crystals (top) [10, 21], NLO compounds (middle) [22], and photochromic materials for holographic data storage (bottom) [23].

Keywords Angle multiplexing Azobenzene Diblock copolymers Holographic data storage Molecular glasses Phase gratings Surface relief gratings... 

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