• Title, Summary, Keyword: Photopolymer film

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Preparation and Holographic Recording of Fluorescent Photopolymer Films Containing Anthracene Polymer for Security

  • Park, Tea-Hoon;Kim, Yoon-Jung;Kim, Jeong-Hun;Kim, Eun-Kyoung
    • Journal of the Optical Society of Korea
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    • v.14 no.4
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    • pp.305-309
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    • 2010
  • Photopolymer films containing fluorescent anthracene polymer, polymethyleneanthracene (PMAn), were prepared with different concentrations of PMAn for holographic recording useful for security documents. The fluorescent photopolymer film showed enhanced fluorescent intensity due to the micro-separation which arose from grating formation and diffusion during photopolymerization. Experimental values of diffraction efficiency were well matched to the simulated values for photopolymers having different PMAn concentrations. Holography patterning was carried out using the fluorescent photopolymer under a photo-mask. A grating was confirmed using microscope techniques in the recorded area under the pattern. Importantly the recorded area showed enhanced fluorescence compared to the unrecorded part, allowing fluorescence patterns at micro scale along with the submicron grating pattern. The fluorescence pattern recorded on the photopolymer film provides additional readability of holographic reading and thus is useful for secure recording and reading of information.

Analysis of Optical Properties with Photopolymers for Holographic Application

  • Kim Nam;Hwang Eun-Seop;Shin Chang-Won
    • Journal of the Optical Society of Korea
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    • v.10 no.1
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    • pp.1-10
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    • 2006
  • Optical transparency and high diffraction efficiency are two essential factors for high performance of the photopolymer. Optical transparency mainly depends on the miscibility between polymer binder and photopolymerized polymer, while diffraction efficiency depends on the refractive index modulation between polymer binder and photopolymerized polymer. For most of organic materials, the large refractive index difference between two polymers accompanies large structural difference that leads to the poor miscibility and thus poor optical quality via light scattering. Therefore, it is difficult to design a high-performance photopolymer satisfying both requirements. In this work, first, we prepared a new phase-stable photopolymer (PMMA) with large refractive index modulation and investigated the optical properties. Our photopolymer is based on modified poly (methyl methacrylate) as a polymer binder, acryl amide as a photopolymerizable monomer, triethanolamine as initiator, and yellow eosin as a photosensitizer at 532 nm. Diffraction efficiency over 85% and optical transmittance over 90% were obtained for the photopolymer. Second, Organic-inorganic nanocomposite films were prepared by dispersing an aromatic methacrylic monomer and a photo- initiator in organic-inorganic hybrid sol-gel matrices. The film properties could be controlled by optimizing the content of an organically modified silica precursor (TSPEG) in the sol-gel matrices. The photopolymer film modified with the organic chain (TSPEG) showed high diffraction efficiency (> 90%) under an optimized condition. High diffraction efficiency could be ascribed to the fast diffusion and efficient polymerization of monomers under interference light to generate refractive index modulation. The TSPEG modified photopolymer film could be successfully used for holographic memory.

Diffraction Efficiency Improvement of PVA/AA/SeO2 Photopolymer with Various Film Thickness and Eosin Y Contents (PVA/AA/SeO2 광고분자 필름의 두께 및 Eosin Y 함량 변화에 따른 회절효율 향상에 관한 연구)

  • Her, Ki-Young;Jang, Hwan-Ho;Kim, Dae-Heum
    • Korean Journal of Optics and Photonics
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    • v.20 no.4
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    • pp.230-235
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    • 2009
  • Photopolymer is evaluated as better material than the others used for hologram storage, due to many advantages, such as high diffraction efficiency, easy processing, and self-developing. In this study, chalcogenide inorganic compound ($SeO_2$) which has optical activity, was added to polyvinyl alcohol/acrylamide photopolymer films. In order to optimize diffraction efficiency of these photopolymer films, we prepared the photopolymer films with various film thicknesses and Eosin Y content. Diffraction efficiency of the photopolymer films were measured using a 532 nm laser at $40^{\circ}$ incident angle. As a result, the phtopolymer film with Eosin Y content of 0.0045 g and thickness of $297{\mu}m$ showed the highest diffraction efficiency (78.70%).

Fluorescent Pattern Generation on the Fluorescent Photopolymer with 2-beam Coupling Method (2-beam Coupling 방법을 이용한 광 고분자 형광 패턴 형성)

  • Kim, Yoon-Jung;Kim, Jeong-Hun;Sim, Bo-Yeon;Lee, Myeong-Kyu;Kim, Eun-Kyoung
    • Korean Journal of Optics and Photonics
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    • v.21 no.1
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    • pp.6-11
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    • 2010
  • Fluorescent photopolymer film was prepared with composition containing acrylate monomer, binder, a visible light sensitive photo initiator, and fluorescent anthracene polymer. A fluorescent grating pattern was inscribed on the photopolymer film using a 2-beam coupling method. A 514 nm laser was coupled to generate a beam-interference pattern. A highly fluorescent diffractive line pattern was formed on the fluorescent photopolymer within 30 sec. of exposure. The fluorescence intensity was highly enhanced in the patterned area, possibly due to the change in the environment of the fluorescent polymers by the photo-polymerization of monomers. Under a photo-mask, a gap electrode pattern was formed of fluorescent gratings with a sub-micron scale, which was matched well to the calculated value ($2.5\;{\mu}m$ and $0.6\;{\mu}m$) based on the refractive index of the photopolymer and beam incident angle ($3.4^{\circ}$, $15^{\circ}$) to the photopolymer surface.

Characterization of Photopolymers films containing triazine methacrylate monomer for photochromic diffractive image formation (광변색 회절 이미지 형성을 위한 트라이아진계 메타아크릴레이트 모노머를 포함한 광고분자 필름의 특성평가)

  • Oh, Hyun-Jin;Lee, Ji-Yea;kim, Eun-Kyoung
    • Transactions of the Society of Information Storage Systems
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    • v.3 no.4
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    • pp.173-177
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    • 2007
  • A photo-reactive methacrylate monomer having triazine as a core component was examined for photochromic diffractive image formation. Photochromic photopolymer films as a recording media contained a monomer mixture of triazine difunctional metharylate (DT) and ethylene glycol phenyl ether acrylate, binder polymer, photo initiator, and a photochromic spiro-oxazine dye. The content of photochromic dye was changed to examine the effect of photochromophore on diffraction efficiency and real holographic image formation. Holographic recording was performed on the photopolymer film by the combination of reference and probe beam. The diffraction efficiency of the photopolymer film in real-time measurement reached a maximum of $\sim90%$ within 30s. It was highly dependent on the photochromophore contents. After holographic recording, the color of the recorded area was changed under UV light (365 nm) and reversibly bleached to original color upon exposure to a visible light source. Films containing only photochromophore without monomer mixture were not reactive under the recording beam (491nm). Diffractive image formation and mechanism of the holographic recording in the presence of photochromophore will be presented.

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Dynamic characteristics and diffraction efficiency of reflection grating in photopolymer (Photopolymer를 이용한 반사형 회절격자의 효율 및 동적특성 분석)

  • Choi, Yoon-Sun;Yoon, Byeong-Ho;Kim, Nam
    • Korean Journal of Optics and Photonics
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    • v.9 no.5
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    • pp.315-320
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    • 1998
  • The characteristics and structures of photopolymer are analyzed in this paper, which recently have various applications in optical information processing and optical memory, Especially, Du Pont's photopolymer OmniDex 706 reflection film is used in many experiments of different exposures and incident angles, and analyzed by the diffraction pattern generated by glass plate's reflection beam. With the dark reaction of the monomer in photopolymerization, dynamic parameters are considered due to the variation of exposure time and diffusion time delay after exposure. The performance of diffraction efficiency is improved by 10%, when an exposure time is 6.25 sec, and a diffusion time delay is 2 minute.

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Effect of Modification of SeO2/Acrylamide Ratios on Diffraction Efficiencies in PVA/AA Photopolymer Films

  • Kim, Dae-Heum;Lim, Ji-Yun;Nam, Seung-Woong;Chung, Dae-Won
    • Journal of the Optical Society of Korea
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    • v.11 no.4
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    • pp.183-191
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    • 2007
  • The highest diffraction efficiency(DE) value after illumination and post-curing of photopolymer films were obtained at the $SeO_2$/Acrylamide(AA) Ratios of AA 3.0 g, $SeO_2$ 1.0g and the DE's were stable values of over 90%. By the addition of $SeO_2$, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests $SeO_2$ slows down the photopolymerization of AA, which enhances the maximum DE value by giving more migration time. DE variation curve for the optimum composition during extended-time illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded by about 8% after photopolymerization due to monomer migration.