The photorefractive effect—a review

Hall, Trevor J.; Jaura, R.; Connors, L. M.; Foote, Peter

doi:10.1016/0079-6727(85)90001-1

Cited by 207 publications

(41 citation statements)

References 69 publications

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“…Mobility, defined as the velocity of charge carriers per unit field strength, is usually independent of the electric field 2) . The charge transporting process for most inorganic PR crystals can be successfully described by the band-transport theory 24) . Organic materials are usually amorphous materials (disordered materials) and possess a very narrow bandwidth.…”

Section: Migration Of Charge Carriersmentioning

confidence: 99%

Development of fully functionalized photorefractive polymers

Wang

2000

Macromol. Rapid Commun.

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In this article, we review recent progress in the area of photorefractive polymers. Photorefractive (PR) polymers are multifunctional materials which combine photoconductivity and electro‐optic response to show a new phenomenon: light‐induced reversible modulation of the refractive index. Because of their multifunctional features, design, synthesis and preparation of these materials exhibiting high performance is an intellectual challenge. Moreover, numerous applications of photorefractive materials in optical devices have been established using inorganic materials. Utilizing the unique features of organic polymeric materials to prepare useful devices is an engineering challenge. In the past several years, research in this area has gained momentum because numerous new materials which possess better characteristic photorefractive parameters than their inorganic counterparts have been synthesized. Several interesting devices have been presented. Two different approaches have been developed to synthesize and prepare PR polymers, namely composite materials and fully functionalized polymers. Both approaches have had success in identifying new materials and in gaining understanding of the design principles of better materials. This paper discusses these aspects and gives a prospective view about this field.

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Section: Migration Of Charge Carriersmentioning

confidence: 99%

Development of fully functionalized photorefractive polymers

Wang

2000

Macromol. Rapid Commun.

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“…Related dua1use applications could include pattern recognition in machine vision or credit card verification. Gunter has reviewed many of the techniques that are used in these devices; and Hall, et al 7 have reviewed the models used to describe the photorefractive response of materials. Wide-gap semiconductors such as the sillenites often contain donors (or acceptors).…”

Section: Introductionmentioning

confidence: 98%

<title>Growth of tailored sillenite photorefractives for optical correlation</title>

1995

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Photorefractives, in general, are among the most promising materials solutions to real time optical correlation. Applications include military target recognition and civilian robotic vision. Crystals of sillenite structure photorefractives, Bi12XO20, where X = Si, Ge, or Ti, have been grown by melt techniques and in the case of bismuth silicon oxide (BSO) and bismuth titanium oxide (BTO) by the hydrothermal method of high-temperature/high-pressure solution growth. The two growth methods are discussed and crystals grown by the two methods are compared in this paper. Optical absorption and TSC studies show that hydrothennal BSO is essentially free of the native antisite Bi defect which usually acts as a donor. These studies also show that the trap density is greatly reduced in hydrothermal material. Preliminary experiments show that hydrothermal BTO crystals have improved properties over melt grown samples. Al and P act as donors and acceptors respectively and can be used to compensate the native anti-site bismuth defect Initial spectroscopy studies show that they can be used to alter the valence state of transition element dopants. This result may aid in "tailoring" these materials.

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“…For later convenience, we define the parameter To derive the degeneracy surface, we set all coefficients equal to zero, at least to first order in From (12) we obtain (37) From (13), and using (37), follows (38) whereas (14) and (37) yield (39) Substituting into (15) results in the following quadratic equation in (40) where (41) (42) (43) Therefore, the degeneracy surface is obtained by setting equal to the root of (40) that is closest to 1 in magnitude and then substituting in (37)- (39). The result for a particular numerical example is shown in Fig.…”

Section: Hologram Degeneracies and Multispectral Tomographymentioning

confidence: 99%