Optical memory devices

These effects open up the possibility of novel magneto-optical memory devices. 

A. A. Angelutc, A. Yu. Chikisev, N. I. Koroteev, S. A. Magnitskii, Yu. P. Meshalkin, I. A. Ozheredov, S. Yu. Orzhancev, V. V. Shubin, and N. T. Sokolyuk, Photochemical and spectroscopic properties of naphthacenequinones. Candidates for 3D optical memory devices, in International Symposium on Optical Memory and Optical Data Storage, 1996 Technical Digest Series, 12, 178-180 (1996). 

Recently, especially since the LLP phenomenon in SrAl204 Eu, Dy was reported in 1996 [1], LLP materials have been extensively investigated due to its potential application in display in the dark, energy storage, enhancement of the conversion efficiency of solar cell and the fabrication of re-writable three-dimensional optical memory devices, etc [2-5],... 

There is no limit to the number of photochromic systems possible. The systems discussed are excellent candidates for integration into solid-state devices because nearly all retain their photochromic properties in the absence of solvent. The organization of these systems in tandem with other molecular systems is being pursued. For the switching applications many of these systems have much too slow a turnover rate to be explored as working devices. That is unless the connectivity in these systems can be increased. In the meantime, photochromic systems will probably be explored as possible optical memory devices. The most promising switches are those based on the much faster processes of electron and energy transfer. We will now examine research in these areas. 

Dvornikov, A. S., Malkin, J., and Rentzepis, P. M. Spectroscopy and kinetics of photo-chromic materials for 3D optical memory devices. J. Phys. Chem. 1994, 98, 6746-6752. 

Optical memory devices such as compact disks (CDs) and digital versatile disks (DVDs) are becoming essential items of audio and visual media as well as of external computer memory media. In these devices, a laser beamis used to record and read information. Because the laser spot can be focused to within a 1 fxm scale, optical memory can access higher density and capacity than conventional magnetic memories can. 

A 3D optical memory device can be based on different principles. Among them are the write once and read many times principle, based on TP initiated photopolymerization resulting in a photopolymer structure [242] or photo-bleaching of a fluorescent material [250]. The rewritable principle is based mainly on TP induced molecular change. This TP induced molecular change can be an isomerization reaction in the writing process and OP induced fluorescence in the reading process [119, 144, 247, 258],... 

The conversion of 4-methoxyflavylium perchlorate into 4 -methoxychalcone in aqueous solution is influenced by pH, heat and light such that either the coloured or colourless molecules can exist as the stable species. Interconversion by changing the conditions offers a potential molecular switching system for an optical memory device <97JA5556>. 

Z-jS- (N-alky 1-4-pyridinium) -a-cyano-4-styryldicyanomethanide is photochromic (see Figure 1) and bleaches when irradiated at wavelengths which overlap the charge transfer band. Bleached solutions recolour in the dark whereas LB films do not revert to their pre-switched form and may be used in optical memory devices. An unusual feature of the LB films is the very sharp charge transfer band at 495 nm with a HWHM of 27 nm (Figure 1)... 

The present time is characterized by the rapid development of studies aimed at the constmction of nanostmctured materials with external-stimuli-controlled physicochemical properties/° ° In this respect, the multifunctional comb-shaped LC polymers offer a vivid example of self-organized thermocontrolled, photocontrolled, and electrically controlled nanostmctured materials (field-responsive smart materials) that show promise for various applications optics, optoelectronics, photonics, display technology, optical memory devices, telecommunications systems, and so on (Chapters 8.08, 8.09 and 8.15). 

Used in recording media, particularly in erasable Possess high temperature stability and high fatigue optical memory devices. resistance usually lack fluorescence but fluorescent... 

Electrochromic device is a generic form of device applications based on PANI. It may include display and optical memory devices, anti-glare car rearview mirrors, sunglasses, protective eyewear for the militaiy use, and smart windows for car and buildings. Recent reports on flexible electrochromic device composed of PANI represents a new area of applications of PANI (12,13). 

The change of color of the photochromic materials upon irradiation with UV light can be used as a UV radiation sensor [125-130] or temperature sensor [131-133], optical memory devices and switches [134-138], and optoelectronic applications [139,140]. Photochromic hybrid coating having a remarkable long-term stability of both the colored and colorless states in the dark (bistability) was reported [141]. 

---