• Title/Summary/Keyword: Diffraction grating

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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.

Ag 두께의 변화에 따른 chalcogenide layer의 회절효율 특성

  • Nam, Gi-Hyeon;Jeong, Hong-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.197-197
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    • 2009
  • We have investigated the holographic grating formation on Ag-doped amorphous chalcogenide AsGeSeS thin films with Ag thickness. Holographic gratings have been formed using Diode Pumped Solid State laser (DPSS, 532.0nm) under [P:P] polarized the intensity polarization holography. The diffraction efficiency was obtained by +1st order intensity.

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Effect of Nano-sized Silicas in HPDLC Based on PUA

  • Kim, Eun-Hee;Woo, Ju-Yeon;Kim, Byung-Kyu
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1212-1215
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    • 2004
  • Diffraction modes of holographic grating were fabricated with polyurethane acrylates(PUA). Two types of silica (AEROSIL 200 and AEROSIL R812) were added to reduce the shrinkage of polymer matrix. It was founded that shrinkage of PUA composite film was reduced with the addition of silica. HPDLC based PUA/silica composite also showed high diffraction efficiency. The morphology of the resultant gratings was analyzed by using scanning electron microscopy(SEM) and Tg of the polymer matrix by dynamic mechanical thermal analysis(DMTA).

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A Study on Dichromated Gelatin for Recording of HOE (홀로그래픽 광학소자 제작을 위한 dichromated gelatin 연구)

  • Man Ho Jeong
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.112-114
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    • 1990
  • A method for fabrication of holographic optical elements (HOE) using dichromated gelatin (DGG) as a recording material is presented. we describe the holographic properties of the DGG and the processing techniques. Holographic characteristics of the DGG including exposure characteristics, diffraction efficiency and angular sensitivity are also discussed. The diffraction efficiency of the obtained holographic grating is about 84%.

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비정질 As2Se3 박막의 Ag 의존적 홀로그래픽 격자 형성 특성 분석

  • Nam, Gi-Hyeon;Kim, Jang-Han;Jeong, Hong-Bae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.275-276
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    • 2011
  • We have investigated the holographic grating formation on Ag-doped amorphous chalcogenide As2Se3 thin films with Ag layer. The basic optical parameter which is a refractive index and extinction coefficent was taken by n&k analyzer. The source of laser was selected based on these parameter. Holographic gratings have been formed using He-Ne laser (wavelength: 632.8 nm) Diode Pumped Solid State laser (DPSS, wavelength: 532.0 nm) under [P:P] polarized the intensity polarization holography. The diffraction efficiency was obtained by +1st order intensity.

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Design of flat-field XUV spectrograph with a toroidal mirror (광집속 Toroidal mirror를 이용한 평면결상)

  • 이병훈;최일우;남창희
    • Korean Journal of Optics and Photonics
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    • v.3 no.2
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    • pp.77-85
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    • 1992
  • The design of a flat-field XUV spectrograph is optimized for a high throughput, aberration-corrected spectral image in the wavelength region of 50-300 $\AA$ The varied-line spacing (VLS) concave grating theory for an XUV spectrograph with a toroidal mirror in front of an entrance slit is derived. Since the derived theory includes the arbitrary shaped source, it is able to correct the limit of the simple optimization theory which considers only a point source at the center of the entrance slit. The reflection matrix at the toroidal mirror and the diffraction matrix at VLS grating are derived and compared with those of a holographic grating. The absolute energy efficiency of a flat-field spectrograph is calculated by considering the reflectivities of the toroidal mirror and the Au coated concave grating and the grating efficiency. The alignment sensitivity of the toroidal mirror and the concave grating is investigated, and the method to achieve the best imaging of XUV spectrum is discussed. The calculated resolving power of the flat-field XUV spectrograph is more than 4000 in the aberration-corrected wavelength range. The focused spot size at the dispersion plane is less than $20\mu \textrm m\times \mu \textrm m$at the wavelength 100$\AA$ It is shown that a high throughput characteristic can also be achieved through a careful adjustment of alignment parameters.

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FABRICATION AND TEST OF AN OPTICAL GRISM (가시광선용 그리즘의 제작과 성능시험)

  • Lee, D.H.;Song, J.W.;Yoon, T.S.
    • Publications of The Korean Astronomical Society
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    • v.28 no.3
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    • pp.75-82
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    • 2013
  • An optical grism for education is fabricated and tested. It is composed of a transmission grating as dispersion element and a prism as diffraction angle compensation device. The transmission grating is Edmundoptics #49-584(spatial frequency 600 lines/mm, dimension $50mm{\times}50mm$). The prism is the fused silica type with angles ($41.3^{\circ}$, $-48.7^{\circ}$, $-90^{\circ}$). The grism device is fabricated by bonding the transmission grating and the prism with an optical adhesive. The zig for assembling the grism, telescope and camera is composed of an aluminum tube, an aluminum disk ring and a T-ring camera adaptor. The fabricated optical grism spectrograph is tested in laboratory using Halogen lamp and Neon lamp with DSLR camera. And the grism assembled with reflector telescope is tested in a field using stellar light. The results show good agreements with design parameters. The wavelength coverage range of the grism is 250 nm at the un-deviated wavelength of 506 nm. The wavelength resolution is 0.11 nm/pixel.

Analysis of Resonance Scattering Characteristics by Multi-layered Dielectric Gratings (다층 유전체 격자구조에 의한 공진 산란특성의 분석)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.1
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    • pp.231-236
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    • 2017
  • The space harmonics generated by a plane-wave incident upon a multi-layered dielectric grating can undergo strong resonance scattering variations known as GMR(guided-mode resonance). To clarify these effects, we examine the field propagation and dispersion curve inside the grating region by using a rigorous equivalent transmission-line theory(RETT). The results show that, at the peak of a scattering resonance, the reflected mode is almost identical to a leaky wave that can be supported by the grating structure. Thus, we confirm and generalize previous research that has occurred GMR effect associated with the free-resonant character of leaky waves at multi-layered dielectric gratings. Quantitative simulation results illustrating the behavior of typical gratings are given, and the special case of normal incidence is discussed for TM mode.

The setup of the moiré deflectometry using the virtual grating and the measurement of the effective focal length (가상격자를 사용한 무아레 무늬 발생기의 구성과 유효초점거리 측정)

  • Kim, Sang Gee
    • Journal of Korean Ophthalmic Optics Society
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    • v.5 no.2
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    • pp.181-186
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    • 2000
  • The setup of the moir$\acute{e}$ deflectometry using the virtual grating was done, so the convergence and divergence of a pencil of ray was determined. The light source was He-Ne laser(3mW). The focal length of the first lens, the second lens being 18 mm, 250 mm respectively was used for the setup of the beam expander. The optics of the moir$\acute{e}$ deflectometry determining the vergence was used a diffraction grating(pitch = $1.6{\mu}m/line$) and a front flat reflection mirror. The effective focal length of the trial lens set was measured and compared with the theoretical value.

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Diffraction Efficiency Properties of Holographic Gratings by the Reversal Bleached on the Effect of Superadditivity (초부가성 효과에 의한 반전표백 홀로그래피 회절격자의 회절효율 특성)

  • Lim, Chun-Woo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.5
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    • pp.403-407
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    • 2010
  • This paper shows that the diffraction efficiency is influenced by superadditivity for the combination of the different developing agent and concentrations in the reversal bleach applied to the Slavich PFG-01 plate to be used for recording transmission holograms. The four developers based on ascorbic acid in combination with metol, phenidone, hydroquinone respectively, were studied. In diffraction efficiency aspect, the superadditivity effect of mixture of two developing agents is lower than one developing agent developer, AAC in the reversal bleach.