• Title/Summary/Keyword: holographic

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Holographic ROM System (홀로그래픽 재생 전용 시스템)

  • 김근율;강병복;조장현;박주연;남하은
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.07a
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    • pp.58-59
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    • 2003
  • 최근 들어 홀로그래픽 데이터 스토리지의 상용화를 위한 많은 연구가 국내외에서 진행되고 있다. 그런데 성공적인 상용화를 위해서는 개발될 시스템의 가격을 낮추고 기존의 광 메모리와 호환성을 갖추는 것이 중요한 과제로 여겨지고 있다. 이를 달성하기 위한 한 방법으로 비트 단위의 기록 재생 방법을 도입한 holographic ROM System이 제안되었다. 이러한 시스템에서는 일반 DVD나 CD와 거의 유사한 구조를 가지고 있어 저렴하면서도 기존의 광 메모리와도 호환성을 갖는 제품을 만들 수 있을 것으로 예측된다. (중략)

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Image Stitching and Seamless Holographic Photo-Lithography for Large-Area Patterning (대면적 리소그래피를 위한 홀로그램 영상의 연결과 연결 영역에서의 간섭무늬 제거)

  • Lee, Joon-Sub;Park, Woo-Jae;Lee, Ji-Whan;Song, Soek-Ho;Lee, Sung-Jin;Kim, Oui-Serg
    • Korean Journal of Optics and Photonics
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    • v.20 no.1
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    • pp.23-28
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    • 2009
  • In this study, we propose an image stitching method for large-area holographic photo lithography. In this method, a hologram medium become a hologram mask for lithography. And the mask has information for stitched images. These images are recorded by signal images which are controlled with DMD (digital micro-mirror device), and serial hologram recording is achieved with a motorized linear stage. Using this method, fringe seams appear on the stitching area. To remove these fringe seams, double exposure holographic lithography is tried. Each stitched image is recorded and reconstructed with a different reference beam. The experiments confirm that fringe seams are removed.

The Formation of Holographic Data Grating on Amorphous Chalcogenide $Ag/As_{40}Ge_{10}Se_{15}S_{35}$ Thin Films with Various Thickness (두께에 따른 비정질 칼코게나이드 $Ag/As_{40}Ge_{10}Se_{15}S_{35}$ 박막의 홀로그래피 데이터 격자형성)

  • Yea, Chul-Ho;Chung, Hong-Bay
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.8
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    • pp.387-391
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    • 2006
  • The Ag photodoping effect in amorphous $As_{40}Ge_{10}Se_{15}S_{35}$ chalcogenide thin films for holographic recording has been investigated using a He-Ne laser (${\lambda}$=632.8 nm). The chalcogenide films thickness prepared in the present work were thinner in comparison with the penetration depth of recording light ($d_p=1.66{\mu}m$). It exhibits a tendency of the variation of the diffraction efficiency (${\eta}$) in amorphous chalcogende films, independently of the Ag photodoping. That is, ${\eta}$ increases rapidly at the beginning of the recording process and reaches the maximum (${\eta}_{max}$) and slowly decreases slowly with the exposed time. In addition, the value of ${\eta}_{max}$ depends strongly on chalcogenide film thickness(d) and its maximum peak among the films with d = 40, 80, 150, 300, and 633 nm is observed 0.083% at d = 150 nm (approximately 1/2 ${\Delta}n$), where ${\Delta}$n is the refractive index of chalcogenide thin film (${\Delta}n=2.0$). The ${\eta}$ is largely enhanced by Ag photodoping into the chakogenides. In particular, the value of ${\eta}_{max}$ in a bilayer of 10-nm-thick Ag/150-nm-thick $As_{40}Ge_{10}Se_{15}S_{35}$ film is about 1.6%, which corresponds to ${\sim}20$ times larger than that of the single-layer $As_{40}Ge_{10}Se_{15}S_{35}$ thin film (without Ag). And we obtained the diffraction pattern according to the formation of (P:P) polarization holographic grating using Mask pattern and SLM.

Servo control for shift-multiplexed holographic data storage by using a dome-type glass (돔 유리를 이용한 위치이동 다중화 홀로그램 정보저장장치용 서보 컨트롤)

  • 김성필;송석호;오차환;김필수;김지덕;이홍석
    • Korean Journal of Optics and Photonics
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    • v.15 no.1
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    • pp.74-78
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    • 2004
  • We propose a servo control method using a dome-type glass in shift-multiplexed holographic data storage. We frist store live 2-D data by shift-multiplexing in a holographic disk with 5% variation in their. diffraction efficiencies. During read-out of the stored data, the servo control using the dome glass correctly compensates mechanical errors of the disk; the error of $\pm$0.2$^{\circ}$and run-out error of $\pm$50 ${\mu}{\textrm}{m}$. Use of the dome-type glass in servo control makes a pickup module more compact in size and easier to control than the previous method using parallel glass plate [Sungphil Kim, et al., Hankook Kwanghak Hoeji, Vol. 14, No. 1, pp.58-64, 2003].

Implementation of Multiview Stereoscopic 3D Display System using Volume Holographic Lenticular Sheet (VHLS 광학판 기반의 다시점 스테레오스코픽 3D 디스플레이 시스템의 구현)

  • 이상우;이맹호;김은수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.5C
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    • pp.716-725
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    • 2004
  • In this paper, a new multiview stereoscopic 3D display system using a VHLS(volume holographic lenticular sheet) is suggested. The VHLS, which acts just like an optical direction modulator, can be implemented by recording the diffraction gratings corresponding each directional vector of the multiview stereoscopic images in the holographic recording material by using the angularly multiplexed recording property of the conventional volume hologram. Then, this fabricated VHLS is attached to the panel of a LCD spatial light modulator and used to diffract each of the multiview image loaded in a SLM to the corresponding spatial direction for making a 3D stereo view-zone. Accordingly, in this paper, the operational principle and characteristics of the VHLS are analyzed and an optimized 4-view VHLS is fabricated by using a commercial photopolymer. Then, a new VHLS-based 4-view stereoscopic 3D display system is implemented. Through some experimental results using a 4-view image synthesized with adaptive disparity estimation algorithm, it is suggested that implementation of a new VHLS-based multiview stereoscopic 3D display system can be possible.

The Dependence of Substrate on Ag Photodoping into Amorphous GeSe Thin Films using Holographic Method (비정질 GeSe 박막으로의 은-광도핑에 대한 기판의존성)

  • Yeo, Jong-Bin;Yun, Sang-Don;Lee, Hyun-Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.10
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    • pp.852-858
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    • 2007
  • The dependence of substrate on the Ag photodoping phenomenon into amonhous $({\alpha}-)$ GeSe thin film has been investigated using holographic method. A 442 nm HeCd laser was utilized as a light source for the holographic exposure and a 632.8 nm HeNe laser to measure the variation of diffraction efficiency $(\eta)$ in real time. The films (Ag and ${\alpha}-GeSe$) were thermally deposited on the substrates, i.e. p-type Si(100), n-type Si(100) and slide glass. The sample structures prepared were two types: type I (Ag/${\alpha}$-SeGe/substrate) and type II (${\alpha}$-SeGe/Ag/substrate). The $\eta$ kinetics comprised to be three steps in which $\eta$ initially increases, is saturated to be maximized $(\eta_M)$, and then decreases relatively gradually. For the same substrate, the $\eta_M$ values of the type II were higher than those of type I. In addition, the type II exhibited the highest $\eta_M$ for p-type Si substrate, while that in type I was observed for n-type Si substrate. These tendency is explained by the diffusion of minority carrier in the films and the change of magnitude and direction in internal fields generated at the film interfaces. Atomic-force-microscope (AFM) was used to observe relief-type grating patterns.

On-axis servo control in pickup actuator for disk type holographic data storage (디스크 형 홀로그램 정보저장장치를 위한 광축상 서보 컨트롤)

  • Kim, Sung-Phil;Song, Seok-Ho;Oh, Cha-Hwan;Kim, Pill-Soo;Kim, Ji-Deog;Lee, Hong-Seok
    • Korean Journal of Optics and Photonics
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    • v.14 no.1
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    • pp.58-64
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    • 2003
  • In order to read correct data from a disk-type holographic storage medium, it is very important to implement a servo-control in the pick-up module, as in a conventional CD-ROM. We propose a novel servo-control method using a glass plate on the optical axis, which is able to compensate the mechanical errors coming from wobbling of holographic disk and spindle motor. By rotating the glass plate within $\pm$10 degrees, we can reduce the reading errors of $\pm$200 ${\mu}{\textrm}{m}$ to $\pm$15 ${\mu}{\textrm}{m}$.