Optical data storage chromophores

Polymers and supermolecules modified using electron push-pull chro-mophores are also of particular interest for nonlinear optics (NLO) [10-15]. NLO material has attracted much interest over the past 20 years and has been widely applied in various field (telecommunications, optical data storage, information processing, microfabrication, etc.). Chemists have developed ways to introduce NLO chromophores into many type of polymers, such as Hnear polymers, cross-linked polymers, and branched polymers, and have demonstrated their performance in NLO appHcations. 

Second, in addition to the above, the fact that many expanded porphyrins are highly colored makes their use as dyes an obvious possibihty. Here their planar nature makes them particularly attractive as chromophores for use in liquid crystals and optical data storage applications. Also, these properties could make them of interest as photo-sensors in various clinical or pseudo-clinical situations. For instance, the high affinity by certain sapphyrins for enveloped viruses and cholesterol rich liposomes suggests that expanded porphyrins could be used to detect and/or destroy a variety of unwanted biological targets, including arterial sclerotic plaque. 

Dumont, M., Hosotte, S., Froc, G., and Sekkat, Z. (1994). Orientational manipulation of chromophores through photoisomerization. In Photopolymers and Applications in Holography, Optical Data Storage, Optical Sensors, and Interconnects. (R. A. Lessard, cd.), Proc. SPIE 2042,2-13. 

Stracke A, Wendorff, JH, Goldmann D, Janietz D. 2000. Optical data storage in a smectic mesophase thermal amplification of light induced chromophore orientation and surface relief gratings. Liq Cryst 27 1049 1057. 

One of the most interesting photoresponsive properties of azo polymers is the photoinduced birefringence and dichroism (Xie et al., 1993). The photoinduced anisotropy is caused by the disparity of the repeated trans-cis isomerization of azo chromophores under linear polarized light irradiation. The most efficient excitation occurs in the polarization direction, which can force the chromophores to continually change their orientation and to be eventually stabilized at the direction perpendicular to the polarization (Natansohn and Rochon, 2002). The effect shows potential applications in areas such as reversible optical data storage, optical switching and sensors. 

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