• Title/Summary/Keyword: Spatial Modulator

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Resolution in Optical Scanning Holography (광스캔닝 훌로그래피의 해상도)

  • Doh, Kyu Bong
    • Journal of Advanced Navigation Technology
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    • v.2 no.2
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    • pp.126-131
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    • 1998
  • In optical scanning holography, 3-D holographic information of an object is generated by 2-D active optical scanning. The optical scanning beam can be a time-dependent Gaussian apodized Fresnel zone plate. In this technique, the holographic information manifests itself as an electrical signal which can be sent to an electron-beam-addressed spatial light modulator for coherent image reconstruction. This technique can be applied to 3-D optical remote sensing especially for identifying flying objects. In this paper, we first briefly review optical scanning holography and analyze the resolution achievable with the system. We then present mathematical expression of real and virtual image which are responsible for holographic image reconstruction by using Gaussian beam profile.

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Quality Enhancement of a Complex Holographic Display Using a Single Spatial Light Modulator and a Circular Grating

  • Bang, Le Thanh;Piao, Yan Ling;Kim, Jong Jae;Kim, Nam
    • Journal of the Optical Society of Korea
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    • v.20 no.1
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    • pp.70-77
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    • 2016
  • This paper proposes an optical system for complex holographic display that enhances the quality of the reconstructed three-dimensional image. This work focuses on a new design for an optical system and the evaluation of the complex holographic display, using a single spatial light modulator (SLM) and a circular grating. The optical system is based on a 4-f system in which the imaginary and real information of the hologram is displayed on concentric rectangular areas of the SLM and circular grating. Thus, this method overcomes the lack of accuracy in the pixel positions between two window holograms in previous studies, and achieves a higher intensity of the real object points of the reconstructed hologram than the original phase-reconstructed hologram. The proposed method provides approximately 30% less NMRS (Normal Root Mean Square) error, compared to previous systems, which is verified by both simulation and optical experiment.

HELIUM3D: A Laser-scanning Head-tracked Autostereoscopic Display

  • Brar, Rajwinder Singh;Surman, Phil;Sexton, Ian;Hopf, Klaus
    • Journal of Information Display
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    • v.11 no.3
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    • pp.100-108
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    • 2010
  • A multi-user autostereoscopic display based on laser scanning is described in this paper. It does not require the wearing of special glasses; it can provide 3D to several viewers who have a large degree of freedom of movement; and it requires the display of only a minimum amount of information. The display operates by providing regions in the viewing field, referred to as "exit pupils," which follow the positions of the viewers' eyes under the control of a multi-user head tracker. The display incorporates an RGB laser illumination source that illuminates a light engine. The light directions are controlled by a spatial light modulator, and a front screen assembly incorporates a novel Gabor superlens. Its operating principle is explained in this paper, as is the construction of three iterations of the display. Finally, a method of developing the display into one that is suitable for television applications is described.

Development of Finite Element Model for Dynamic Characteristics of MEMS Piezo Actuator in Consideration of Semiconductor Process (반도체 공정을 고려한 유한요소해석에 의한 MEMS 압전 작동기의 동특성 해석)

  • Kim, Dong Woohn;Song, Jonghyeong;An, Seungdo;Woo, Kisuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.454-459
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    • 2013
  • For the purpose of rapid development and superior design quality assurance, sophisticated finite element model for SOM(Spatial Optical Modulator) piezo actuator of MOEMS device has been developed and evaluated for the accuracy of dynamics and residual stress analysis. Parametric finite element model is constructed using ANSYS APDL language to increase the design and analysis performance. Geometric dimensions, mechanical material properties for each thin film layer are input parameters of FE model and residual stresses in all thin film layers are simulated by thermal expansion method with psedu process temperature. $6^{th}$ mask design samples are manufactured and $1^{st}$ natural frequency and 10V PZT driving displacement are measured with LDV. The results of experiment are compared with those of the simulation and validate the good agreement in $1^{st}$ natural frequency within 5% error. But large error over 30% occurred in 10V PZT driving displacement because of insufficient PZT constant $d_{31}$ measurement technology.

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Incoherent Optical Signal Processor Using an Acousto-Optic Modulator and a Scanner (어쿠스토옵틱 광변조기와 스캐너를 사용한 인코히런트 광신호 처리기)

  • Park, Jin-Woo
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.12
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    • pp.2016-2024
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    • 1989
  • A versatile incoherent optical processing system is developed and analyzed in detail, in which an acousto-optic modulator is used to generate the temporal offset frequency for heterodyning and an optical scanner to process the input object in scanning mode. The operational characteristics of the systems are studied with respect to spatial filtering in terms of the spectral width change of the light source, the temporal offset frequency, and a scanning rate. To enhance the system's capability, two schemes for tuning the system's OTF, structural tuning and defocused object tuning, are also developed and verified with the MTF measurements and computer calculations.

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Controlling the Intensity Distribution of Light at the Output of a Multimode Optical Fiber Using a Polar-coordinate-based Transmission-matrix Method (극좌표 기반 투과 매트릭스 방법을 이용한 다중모드 광섬유 출력단에서의 빛의 세기 분포 제어)

  • Park, Jaedeok;Jo, Jaepil;Yoon, Jonghee;Yeom, Dong-Il
    • Korean Journal of Optics and Photonics
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    • v.33 no.6
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    • pp.252-259
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    • 2022
  • We have conducted a study to control the light-intensity distribution at the output end of a multimode optical fiber via estimating the transmission matrix. A circularly arranged Hadamard eigenmode phase distribution was implemented using a spatial light modulator, and the transmission matrix of a multimode optical fiber was experimentally obtained using a four-phase method. Based on the derived transmission matrix, the spatial phase distribution of light incident upon the optical fiber was adjusted via the spatial light modulator in advance, to focus the light at a desired position at the optical fiber output. The light could be focused with an intensity up to 359.6 times as high as that of the surrounding background signal at a specific position of the multimode fiber's output end, and the intensity of the focused beam was on average 104.6 times as large as that of the background signal, across the area of the multimode fiber's core.

Recent Technology of 3D Content for Digital Holography (디지털 홀로그래피 콘텐츠 기술)

  • Yoon, M.S.
    • Electronics and Telecommunications Trends
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    • v.32 no.5
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    • pp.49-64
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    • 2017
  • Digital holography is a computational operation and photo-electronic technology that enables calculating, encoding, and reconstructing a 3D scene based on the interference of a coherent light-wave field. The spatial light modulator in a holographic 3D display decodes a computer-generated hologram to optically regenerate a 3D scene in various depths, thus facilitating to match convergence and accommodation of the human eyes. This paper introduces recent technologies related with the content for digital holography called an ultimate 3D display.

Polarization dependent 2$\times$2 optical switch using FLC(ferroelectric liquid crystal) SLM(Spatial Light Modulator) (FLC SLM을 이용한 편광의존형 2$\times$2 광 스위치)

  • 김인태;유연석
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.262-263
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    • 2002
  • 오늘날 정보화 사회가 세계적으로 구축됨에 따라 초고속 광네트워크 사이의 통신용량의 급격한 증가로 인하여 대용량의 정보를 초고속으로 처리할 광스위치의 필요성이 심각하게 대두되고 있다.[1] 현재 연구되고 있는 광스위치 중에는 광도파로 형테와 MEMS형, 기계식 형태가 있다.[2] 그러나 이들 형태의 광스위치는 대용량과 초고속이라는 두 개의 기능을 동시에 수행하기에는 기술적 어려움이 있다. (중략)

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Phase Hologram : Kinoform (위상 홀로그램 : 키노폼)

  • Kim, Jin-Tae
    • Broadcasting and Media Magazine
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    • v.16 no.2
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    • pp.129-135
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    • 2011
  • Basic principles of kinoform which is a phase hologram, kinoform design using a modified iterative Fourier transform algorithm, and display technology of the kinoform using a spatial light modulator are introduced. Kinoform applications, domestic, and international research trends for those are also introduced.

Wavefront 3D Reconstruction and Measurement for Natural 3D Display System

  • Matoba, Osamu;Nitta, Kouichi;Awatsuji, Yasuhiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.935-938
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    • 2008
  • Three-dimensional (3D) display systems based on wavefront reconstruction are presented. To obtain the wavefront of 3D objects, we present holographic recording using temporally or spatially phase-shifting interferometer. In the 3D display systems, phase-only reconstruction using a spatial light modulator and an approach to increase the reconstructed power are presented.

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