Fully Functionalized Photorefractive Polymethacrylates with Net Gain at 780 nm

Steenwinckel, David Van; Engels, Chris; Gubbelmans, Elke; Hendrickx, Eric; Samyn, Celest; Persoons, André

doi:10.1021/ma992093e

Cited by 32 publications

(23 citation statements)

References 20 publications

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“…In comparison with some highly efficient PR polymers that have been reported 7,16,24 , the PR performance of our samples is rather small. However, these values are similar or even larger than those reported for other PR devices with higher chromophore content at the same applied external electric field E = 72.7 V/µm 25,26 (diffraction efficiency increases with the fourth power of the external field 27 ). Furthermore, in terms of photonic applications, with just 3 % of diffraction efficiency is possible to: have holographic reconstruction 27 .…”

Section: Resultssupporting

confidence: 83%

Organic photorefractive polymer based in a nonlinear optical chromophore boronate derivative

et al. 2006

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The preparation and characterization of organic photorefractive polymer composites derived from (2-(p-chlorophenyl)-(3'-nitrobenzo[d])-(4''-methoxybenzo[h])-1,3-dioxa-6-aza-2-boracyclonon-6-ene, a push-pull boronate, which shows NLO properties, are described. The polymers are based in the photoconductor poly(9-vinylcarbazole) and the plasticizer 9-ethylcarbazole PVK:ECZ matrix, and C 60 as sensitizer. For the photorefractive performance, two different chromophore concentrations were used, in addition, the ratio of PVK:ECZ was varied to see the effect on the room temperature molecular orientation. Holographic experiments in a tilted four and two wave mixing geometry were performed by using a 10 mW He-Ne laser (632.8 nm). The experiments were performed at room temperature, with a fixed grating spacing Λ of 2.9 µm, for determining the electric field steady-state diffraction efficiency dependency and the optical gain of the composites. Acceptable photorefractive properties were observed for a polymer with a glass transition temperature T g of 77 °C. Even at this T g , the response time was less than one second.

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Section: Resultssupporting

confidence: 83%

Organic photorefractive polymer based in a nonlinear optical chromophore boronate derivative

et al. 2006

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“…A diffraction efficiency of 60% and an optical gain of 57 cm − 1 were observed for the functionalized polymer having R3 NLO moiety with 1 wt% (2,4,7-trinitro-9-fluorenylidene)malononitrile (TNFDM) under E = 58 V μm − 1 at 780 nm. 95 The PR performance of a series of PR polymethacrylates containing carbazoles and Disperse Red dye moieties was investigated at 780 nm. An optical gain coefficient of 140 cm − 1 was measured with incorporation of a TNFDM sensitizer.…”

Section: Plasticizersmentioning

confidence: 99%

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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“…The use of high-T g polymers has been investigated as one means of addressing this problem. 20,21 In such stiff materials, the reorientation of chromophores is restricted, and refractive index modulation is solely due to the Pockels effect. Although rapid response times have been achieved in these materials, the reported diffraction efficiencies are lower than in low-T g materials due to the absence of a supplementary orientational mechanism.…”

Section: Photorefractive Effect Of Ferroelectric Lcsmentioning

confidence: 99%

Photorefractive Effect of Liquid Crystalline Materials

Sasaki

2005

Polym J

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ABSTRACT:This paper reviews our recent work on the photorefractive effect in liquid crystalline materials. The photorefractive effect is defined as the optical modulation of the refractive index of a medium as a result of various processes. The interference of two laser beams in a photorefractive material establishes a refractive index grating. This phenomenon enables the creation of different types of photonic applications. Recently, the development of organic photorefractive materials has been attracting great interest. Liquid crystalline materials are a strong candidate for practical photorefractive materials and application. In this paper, the photorefractivity of liquid crystalline polymers and ferroelectric liquid crystals is described. [DOI 10.1295 The photorefractive effect is a phenomenon wherein a change in the refractive index of a material is induced by the absorption of light. The change in refractive index through the photorefractive effect occurs only within the interference fringes of incident laser beams. When laser beams interfere in a photorefractive material, charge separation occurs between the light and the dark positions of the interference fringes. A space-charge field, an internal electric field, develops at the areas between the light and the dark positions. The refractive index of the corresponding areas is changed through an electro-optic effect. Thus, a refractive index grating is formed at the interference fringes.Dynamic volume-holograms are easily formed through the photorefractive effect, and this has direct applicability in photonics, including optical image processing, parallel optical logic, fringe recognition, and phase conjugation. The photorefractive effect was first observed in the inorganic crystal lithium niobate in 1967.1 It was also subsequently observed in an organic material in 1990.2 Several reviews on the development of photorefractive materials have been published. [3][4][5][6][7] The photorefractive effect has been reported in several organic materials since 1990, such as glassy polymers, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] low-molecular-weight nematic liquid crystals, 24-28 liquid crystalline polymers, [29][30][31][32][33][34][35] ferroelectric liquid crystals, 36-42 polymer/liquid crystal composites 43-55 and amorphous compounds, 56,57 and extremely high photorefractivity values have been achieved in organic polymeric materials. The high photorefractivity in polymeric materials arises from changes in the orientations of the chromophores induced by the internal electric field, termed orientational enhancement. 4,15,17 The photorefractive efficiency of organic materials is several times that of inorganic photorefractive crystals. In addition, organic polymers can easily be processed into films and fibers. This is a significant advantage for applications in photonics.

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Fully Functionalized Photorefractive Polymethacrylates with Net Gain at 780 nm

Cited by 32 publications

References 20 publications

Organic photorefractive polymer based in a nonlinear optical chromophore boronate derivative

Organic photorefractive polymer based in a nonlinear optical chromophore boronate derivative

Molecular design of photorefractive polymers

Photorefractive Effect of Liquid Crystalline Materials

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