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Organic photorefractive materials

About: Organic photorefractive materials is a research topic. Over the lifetime, 697 publications have been published within this topic receiving 13041 citations.


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Proceedings ArticleDOI
23 Aug 1995
TL;DR: The photorefractive effect is a reversible mechanism of holographic grating formation in electro-optic materials, that has potential applications in integrated optics, optical data storage, optical computing, and several other areas as discussed by the authors.
Abstract: The photorefractive effect is a reversible mechanism of holographic grating formation in electro-optic materials, that has potential applications in integrated optics, optical data storage, optical computing, and several other areas. This effect was recently observed in photorefractive polymers doped with charge transport agents. The grating formation is initialized by the photoconductive response which includes charge generation, mobility, and trapping, occurring in successive order. Finally, the grating is formed as a result of modulation of the refractive index by the resulting space charge field, via the electro-optic (Pockels) effect. We present the results of photoconductive measurements as a function of temperature, applied electric field, and illuminated intensity. The investigation is focused on the nonlinear optical polymer bisphenol A 4-4-nitroaminostilbene mixed with 30 weight % of the hole transport agent diethylamino-benzaldehyde diphenyl hydrazone. We observed that the photoconductivity of the photorefractive polymer has the form exp[ aE1/2 + bE1/2/T2 - c/T2] in agreement with the diorder theory of the well- known hopping model developed for charge-transport in molecularly doped polymers. We also observed that the apparent hopping distribution bandwidth increases with increased intensity, consistent with an increasing density of states.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

5 citations

Journal ArticleDOI
TL;DR: In this article, the authors derived the analytical form for index-contrast growth during hologram formation in a photorefractive polymer composite, and showed that index contrast growth is characterized by the rise time of the space-charge field and the rotational diffusion constant.
Abstract: The derivation of the analytical form for index-contrast growth during hologram formation in a photorefractive-polymer composite is presented. The transfer function for chromophore rotation in an amorphous medium is found initially, and this is then convolved with an exponentially growing space-charge field to determine the index-contrast transient. This analysis reveals that index-contrast growth is fully characterized by just two parameters: the rise time of the space-charge field and the rotational diffusion constant. Good agreement between theory and measurement is found for a range of materials and experimental conditions.

5 citations

Journal ArticleDOI
TL;DR: In this article, the photorefractive effect and the thermal effect were investigated in LiNbO3: Fe sheet and Z-scanning method was used to determine the threshold light intensity above which the photo-optical effect was overwhelmed by thermal effect.
Abstract: The lens-like effects, both photorefractive effect and thermo-optical effect, were studied in the LiNbO3: Fe sheet. The threshold light intensity above which the photorefractive effect was overwhelmed by the thermal effect was determined and the thermo-optical coefficient dn/dT is evaluated by the Z-scanning method. The limiting characteristics of LiNbO3: Fe sheet is examined.

5 citations

Journal ArticleDOI
TL;DR: The field dependent photogeneration efficiency is introduced into the complete reorientational model to provide a full account of the electric field and geometrical dependence of the index contrast.
Abstract: Detailed analysis of the relationship between the experimental geometry and the holographic contrast in photorefractive polymers is important for applications, such as angle multiplexing in holographic data storage. In this paper the field dependent photogeneration efficiency is introduced into the complete reorientational model to provide a full account of the electric field and geometrical dependence of the index contrast. The interaction of a local grating and the photorefractive grating is also considered. A simplification for acute angles between writing beams is described. Experimental verification by use of four-wave mixing and transmission ellipsometry reveals an excellent agreement between theory and measurement.

5 citations

Journal ArticleDOI
TL;DR: The dependence of self-pumped photorefractive two-beam coupling in Fe:KNbO3 with crystal angle has been measured at 532 nm for the a-c and b-c crystal planes using a combination of oil immersion and relay imaging.
Abstract: : The dependence of self-pumped photorefractive two-beam coupling in Fe:KNbO3 with crystal angle has been measured at 532 nm for the a-c and b-c crystal planes using a combination of oil immersion and relay imaging. A significant deviation between existing theory and experiment is found for large crystal angles. We propose this is due to a highly anisotropic effective charge trap density in Fe:KNbO3 of almost two orders of magnitude variation with crystal angle in the a-c plane.

5 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231
20211
20201
20181
20172
20165