Asymmetric Energy Transfer in Photorefractive Polymer Composites Under Non-Electric Field

Tanaka, Akiyoshi; Nishide, Junichi; Sasabe, Hiroyuki

doi:10.1080/15421400902939074

Cited by 15 publications

(13 citation statements)

References 7 publications

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“…In this study, we employed the guest-host system for the ACzE/PMMA films and used one of the better known ratios for an azo-carbazole/PMMA system (30/70 wt%). 33,34 The ACzE monolithic dyes with different substituents, NO 2 , CN, CH 3 CO, F, CH 3 O, OH and NH 2 , were mixed with PMMA in tetrahydrofuran. The mixtures were left stirring overnight and then cast on a hot plate at 70°C for 24 h. The obtained composites were sandwiched between two glass plates at 240°C.…”

Section: Methodsmentioning

confidence: 99%

Molecular design of azo-carbazole monolithic dyes for updatable full-color holograms

et al. 2016

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For the use of updatable full-color holography in practical applications, azo-carbazole (ACzE) monolithic dyes dispersed in poly (methyl methacrylate) (PMMA) films with high diffraction efficiency, write/delete capabilities and transparency are of extreme importance. We synthesized seven types of novel ACzE monolithic dyes and examined the influence of substituents introduced in the para position of the phenyl ring and the distinct strength of the substituents (NO 2 : NACzE, CN: CACzE, CH 3 CO: AACzE, F: FACzE, CH 3 O: MACzE, OH: HACzE and NH 2 : AmACzE) on the phenyl ring of the ACzEs. Spectroscopic and holographic optical properties, including absorption coefficient α, wavelength dependence of diffraction efficiency η, response time τ, the thickness of the recorded gratings d, the Bragg angle ΔW and the Q-factor, required for the optimization of updatable full-color holograms were investigated. On the basis of the spectroscopic and holographic optical results, the appropriate writing/reading beams were determined as follows: 561/4600 nm for NACzE, 532/4560 nm for CACzE (and AACzE), 491/4530 nm for MACzE (and HACzE). According to the spectroscopic and holographic optical results, we propose here an insight designed to allow updatable full-color holography using ACzEs, and demonstrate a multi-color hologram in MACzE/PMMA.

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Section: Methodsmentioning

confidence: 99%

Molecular design of azo-carbazole monolithic dyes for updatable full-color holograms

et al. 2016

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“…However, several reports on asymmetric two-beam-coupling gains without the application of an external electric field have been reported for carbazole-based PR polymers, 93,94,111,112 azobenzene derivatives in matrices 113 and carbazole-azobenzene monolithic compound-based PR polymers. [114][115][116] Asymmetric two-beam coupling has also been reported in high T g non-poled PR polymers with carbazole and azobenzene moieties as pendant groups. 117 A large optical gain coefficient exceeding 1000 cm − 1 was observed in a sol-gel matrix doped with Disperse Red 1 (DR1) in the absence of an external electric field.…”

Section: Pr Response In a Centrosymmetric Environmentmentioning

confidence: 99%

“…By using a degenerate four-wave mixing technique, a distorted image passing through a phase-disordered medium was interfered with a reference beam in a PSX-Cz/DB-IP-DC/TNF PR composite 132 and a carbazole-azobenzene monolithic compoundbased PR medium. 116 A counter-propagated probe beam could read out the phase-conjugate wave of the distorted image as a diffracted wave. A diffracted phase-conjugated distorted image was propagated back through a phase disorder medium to restore the original wave front.…”

Section: Pr Response In a Centrosymmetric Environmentmentioning

confidence: 99%

“…A diffracted phase-conjugated distorted image was propagated back through a phase disorder medium to restore the original wave front. 116,132 Optical computing and image amplification PR materials can be used in optical information processing, such as processing of real-time optical data, detecting image correlations, optical interconnections, optical neural networks and optical computing. 12 PR optical gains due to asymmetric energy transfer are a unique feature that can be utilized to amplify original images.…”

Section: Pr Response In a Centrosymmetric Environmentmentioning

confidence: 99%

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Molecular design of photorefractive polymers

Tsutsumi

2016

Polym J

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This review article describes the current state-of-the-art research on organic photorefractive polymer composites. A historical background on photorefractive materials is first introduced and is followed by a discussion on the opto-physical aspects and the mechanism of photorefractivity. The molecular design of photorefractive polymers and organic compounds is discussed, followed by a discussion on optical applications of the photorefractive polymers. Polymer Journal (2016) 48, 571-588; doi:10.1038/pj.2015.131; published online 27 January 2016 BACKGROUND In this report, the molecular design of organic photorefractive (PR) polymers is reviewed. Organic PR polymers are materials that possess both electro-optical and photoconductive properties. Research on photoconductive polymers, whose pioneering polymer is poly(N-vinyl carbazole) (PVK, PVCz), began in the 1960s. From the 1980s, research on organic nonlinear optical (NLO) materials has been widely conducted in the fields of organic electro-optics and optical nonlinearity. From the 1990s, new technology using organic photorefractivity combined with photoconductive and electro-optical properties was introduced in the field of organic semiconducting materials, 1 and organic light-emitting diodes 2-6 and organic fieldeffect transistors 7 were also debuted in this field. At the same time, the interest of researchers also turned toward the development of organic photovoltaic cells and organic solar cells. [8][9][10][11] The transport of charge carriers through photoconductive manifolds is a common phenomenon found in PR, organic light-emitting diode or organic photovoltaic materials. Thus, the development of materials in each field is expected to merge together to trigger the development of novel materials.The PR effect is a well-known phenomenon that is observed in materials in which refractive index modulation is induced by the space-charge field that results from the redistribution of positive and negative charge carriers separated through photo-excitation. 12 This phenomenon was first reported in inorganic crystals of lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ) and was observed through heterogeneous optically induced refractive indices in 1966. 13 Since then, the PR effect has extensively been investigated in many inorganic crystals, and theoretical approaches have been established to explain this phenomenon. 14 In 1991, 1 the first study of PR polymers reported a low diffraction efficiency of 10 −3 to 1% and a small optical gain of 0.33 cm À1 . In 1994, 15 a high diffraction efficiency of 86% (the remaining 14% was attributed to optical losses) and a large optical gain exceeding 200 cm À1 was reported in photoconductive PVK-based PR composites. Over the past two decades, many featured review articles [16][17][18][19][20][21][22][23][24][25][26][27] and book

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“…We have investigated 3-[(4-nitrophenyl)]azo-9H-carbazole-9-ethanol [NACzEtOH, see Fig. 1 [20,21]. This type of material was first developed by Li et al of Wuhan in China as a chromophore attaching to the side chain of polyphosphazene [22].…”

Section: Introductionmentioning

confidence: 99%

Photoinduced grating formation in a polymer containing azo-carbazole dyes

et al. 2012

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Although some azo-carbazole derivatives attached on or doped into inert polymers are known to show photorefractive effect without external electric field, the origin of their asymmetric energy transfer in two-beam coupling experiments were unknown. We made the two-beam coupling experiment followed by sample translation and one-beam diffraction at 633 nm for thick films composed of 3-[(4-nitrophenyl)]azo-9H-carbazole-9-ethanol (NACzEtOH) and poly(methylmethacrylate), finding that photoinduced gratings grew in several minutes accompanied with phase displacement of the gratings, but the phase shift was not always synchronized with the refractive index modulation. We reformulated the Kogelnik's coupled-wave theory with strict energy conservation law for analysis. Comparison of the grating growth and erasure at 532 nm to Disperse Red 1 (DR1), the most well-known azo dye showed that the photoisomerization was dominant at this wavelength and that the azo-carbazole dyes were faster in response time and more resistive to erasure than DR1.

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Asymmetric Energy Transfer in Photorefractive Polymer Composites Under Non-Electric Field

Cited by 15 publications

References 7 publications

Molecular design of azo-carbazole monolithic dyes for updatable full-color holograms

Molecular design of azo-carbazole monolithic dyes for updatable full-color holograms

Molecular design of photorefractive polymers

Photoinduced grating formation in a polymer containing azo-carbazole dyes

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