• Title/Summary/Keyword: holographic

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Holographic Grating Erasing Characteristics by Non-polarized Beam in Amorphous Chalcogenide Thin Films

  • Lee, Ki-Nam;Park, Jeong-Il;Chung, Hong-Bay
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.3
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    • pp.141-144
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    • 2006
  • In the present work, we investigated the holographic grating erasing method by means of the optical method. It was formed the grating under the interference of holographic recording He-Ne laser beams on chalcogenide $As_{40}Ge_{10}Se_{15}S_{35}$ thin film with various film thickness and erased the holographic grating by non-polarized He-Ne laser beam. As the results, the recording grating erased the 80 % of formed grating by non-polarized He-Ne laser beam. It was confirmed that the erasing characteristics by non-polarized laser beam need to improve the focusing of beam and the control of beam intensity. And then it can be expected as the application possibility of rewritable holographic memory technology.

A Study on thin relief phase holographic grating using photoresist. (Photoresist을 이용한 Thin relief 위상형 홀로그램 격자에 관한 연구.)

  • Shin, K.Y.;Choi, D.H.;Kim, N.;Park, H.K.
    • Proceedings of the KIEE Conference
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    • 1987.07a
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    • pp.47-50
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    • 1987
  • There are various holographic recording materials, such as Dichromated Gelatin, Silver Halide, Thermoplastic, Photoresist. In this paper especially, we used Photoresist to make the phase holographic grating. Deep-groove diffractive grating formed in relatively thin holographic recording material is to express high diffraction efficiency. Phase holographic grating recorded In photoresist can be used very practical because it has the high diffraction efficiency, and it is possible to make a replication easily. So, it has the merit in recording the optical holographic grating than any other materials.

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On holographic Wilsonian renormalization group of massive scalar theory with its self-interactions in AdS

  • Gitae Kim;Jae-Hyuk Oh
    • Journal of the Korean Physical Society
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    • v.80
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    • pp.30-36
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    • 2022
  • Holographic model of massive scalar field with its self-interaction λϕn in AdS space is able to give a logarithmic scale dependence to marginal multi-trace deformation couplings on its dual conformal field theory, where λ is the self-interaction coupling of the scalar field, ϕ, and n is an integral number. In arXiv:1501.06664, the authors realize this feature by looking at bulk scalar solutions near AdS boundary imposing a specific boundary condition between the coefficients of non-normalizable and normalizable modes of the scalar field excitations. We study the same holographic model to see scale dependence of marginal deformations on the dual conformal field theory by employing completely different method: holographic Wilsonian renormalization group. We solve Hamilton-Jacobi equation derived from the holographic model of massive scalar with λϕn interaction and obtain the solution of marginal multi-trace deformations up to the leading order in λ. It turns out that the solution of marginal multi-trace deformation also presents logarithmic behavior in energy scale near UV region.

Numerical Reconstruction of Holographic Stereogram with Radial Distortion (방사 왜곡을 포함하는 홀로그래픽 스테레오그램의 수학적 복원)

  • Park, Jiyong;Kang, Hoonjong;Hong, Sunghee;Jung, Kwangmo;Lee, Seunghyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.10
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    • pp.911-919
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    • 2013
  • Evaluation of the effect of radial distortion for a holographic stereogram demands conducting an experiment which comprises rendering of a 3D obejc, acquisition of perspective images, rearrangement of the acquired images for hogel images and quality assessment of the observing image reconstructed from the holographic stereogram. We propose numerical implementation of this evaluation by a specially developed algorithm for modeling of all required steps. The modeling is done by using a numerical model of an optical engine for generation of radially distorted hogel images at various degrees of distortion. The distorted images are used to form the holographic stereogram and to make the numerically reconstructed images from the holographic stereogram which are observed by an observer at desired location. The reconstructed images are compared by using PSNR.

Quantitative Interpretation of Holographic Fringe by Using Phase Shifting Method and Digital Image Processing (위상변이법과 디지탈 영상처리를 이용한 홀로그래피 간섭무늬의 정량적 해석)

  • 고영욱;권영하;강대임;박승옥
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1728-1735
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    • 1992
  • Holographic interferometry technique has been used for the measurement of whole-field deformation with high sensitivity. However there are some difficulties in quantitatively analyzing the holographic fringes. Recently, quantitative and automatic fringe analysis by using phase shifting method in interferometry has been studied in many fields. In this paper, a real time holographic interferometry system and a phase shifting method combined with digital image processing technique are employed to record and quantitatively analyze holographic fringe patterns. To evaluate our system and analyze errors, comparison of measured deformation with theoretical deformation of cantilever beam was carried out. The accuracy of 4.5% in our system was verified We have tried to apply this method to quantitatively measure the deformation of turbine blade under the bending force.

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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EXPERIMENTAL STUDY OF THE CENTER OF RESISTANCE OF A MAXILLARY CANINE USING LASER SPECKLE INTERFEROMETRY AND HOLOGRAPHIC INTERFEROMETRY (상악 견치의 저항 중심에 관한 Laser speckle interferometry와 holographic interferometry볼 이용한 실험적 연구)

  • Lee, Soo Ryong
    • The korean journal of orthodontics
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    • v.18 no.2
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    • pp.289-308
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    • 1988
  • The center of resistance is a important determining factor of tooth movement pattern. Laser speckle interferometry, recently developed for noninvasive measurement of small displacements (microns), was used to detect the center of resistance of a maxillary canine which has normal tooth axis and distal curved root in dry human skull. Laser holographic interferometry was used to verify the results of laser speckle interferometry The following result were obtained; 1. In measurement of the degree of rotation, center of resistance was localized when the traction line passed 4.4/18.0 level from alveola crest to root apex. 2. In measurement of the degree of tipping, center of resistance was localized when the traction line passed 4.6/18.0 level from alveola crest to root apex. 3. In holographic determination, the center of resistance was observed when the traction line passed between 3mm to 6mm level from alveola crest to root apex, therefore the results using laser speckle interferometry was coincided with holographic results.

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Quality Evaluation and Standardization Trend of Holographic Displays (홀로그래픽 디스플레이 화질 평가 및 표준화 연구 동향)

  • Nam, J.;Oh, K.J.;Park, M.;Kim, J.
    • Electronics and Telecommunications Trends
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    • v.32 no.5
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    • pp.65-73
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    • 2017
  • A holography technique optically reconstructs a three-dimensional object in space to provide a natural sense of depth and volume to the observer, thereby providing an ultimate 3D image capable of solving the problem of "vergence-accommodation conflict" occurring in a conventional stereoscopic imaging system. In this paper, we present a technical framework for measuring the performance and evaluating the quality of a holographic display, which enables a quantitative measurement of the optical and physical properties that affect the performance and quality of a holographic display. In addition, we provide the trend regarding standardization related to holographic display measurements. Although this trend has barely started, research activities related to holographic display measurements and quality evaluations are expected to grow in the near future.

Analysis of Three-Dimensional Natural Convection Using a Holographic Interferometric Tomography (홀로그래피 간섭 토모그래피를 이용한 3 차원 자연대류 해석)

  • Shim, Dong-Sik;Lee, Soo-Man;Kang, Bo-Seon;Cha, Dong-Jin;Joo, Won-Jong
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.497-502
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    • 2001
  • Three-dimensional natural convection from a discrete flush-mounted circular heat source on the bottom of a cubic enclosure was studied by using a holographic interferometric tomography. The heat source was located at the off-center of the bottom plate so that three-dimensional temperature field can be achieved. A set of multidirectional holographic interferogram was recorded by employing a double-reference beam, double-exposure holographic technique in order to eventually reconstruct the temperature fields. The recorded interferometric data appear good enough to be further processed to extract optical pathlength data from them and finally reconstruct the temperature fields. A complete analysis of the temperature fields including the field reconstructions and comparison with thermocouple measurements is underway and will be reported shortly.

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