• Current Optics and Photonics
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• 제5권3호
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• pp.261-269
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• 2021

Binary-phase complex spatial light modulators (BP-C-SLMs) are proposed and simulated. This study shows that bottom-top mirror-symmetrical uniaxial systems between two orthogonal polarizers allow one to construct BP-C-SLMs. BP-C-SLMs double the information-handling capacity per pixel, compared to the conventional amplitude-only spatial light modulators (A-SLMs), as well as being simply implemented with a single spatial light modulator (SLM), rather than a combination of an A-SLM and a binary-phase SLMs. Under limited conditions, BP-C-SLMs can control only the amplitude in single-phase space, and act as A-SLMs.

• 한국항행학회논문지
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• 제12권6호
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• pp.659-665
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• 2008

본 논문에서 우리는 PAL-공간변조기를 사용한 Two-pupil 광학 스캐닝 기술에 의하여 실시간 JTC 상관 광 시스템을 수행할 수 있음을 보여주고자 한다. 광학적 addressing(Optical addressing)은 빛에 민감한 $\alpha$-Si 층, 즉 액체 크리스털을 따라 전기장을 조절하는 얍은 층에 의하여 성취되었다. 제안된 기술은 광학적 Twin-pupil 헤테로다인 스캐닝(heterodyne scanning)에 근거하고 있으며, 이 기법은 Fourier 평면에 위치한 광 공간변조기와는 독립적으로 작용한다. 우리는 본 기술의 이론적 근거를 개발하고 목표이미지와 참조이미지 사이의 상관관계를 실험적으로 평가함으로서 본 기술의 성능을 평가하였다.

• 한국광학회지
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• 제10권1호
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• pp.32-39
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• 1999

본연구에서는 연속적으로 세기 분포를 갖는 CGH 패턴을 두 가지 서로 다른 방법으로 이진화를 하고 그 패턴을 LCSLM(liquid crystal spatial light modulator)에 적용하여 재생 특성을 비교해 보았다. 이진화 방법으로는 에러확산 알고리즘과 직접 얀자화 방법을 사용하였다. 재생 특성 비교에 사용한 인자들은 전체 밝기 평균, 평균 제곱 에러, 그리고 회절 효율이다. 실험에 사용한 LCSLM은 256$\times$256 점들을 가지고 87% fill factor와 15$\mu$m pixel pitch를 가지는 이진의 전기적으로 어드레스되는 반사형 강유전성 액정 공간 광 변조기이다.

• 한국자기학회지
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• 제10권2호
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• pp.93-98
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• 2000

자기 광학 공간 광 변조기의 화소의 자화를 반전시키기 위하여 사용하는 드라이브 라인의 형상을 컴퓨터 시뮬레이션을 통하여 설계하고, 연자성막을 도입함으로써 화소 반전에 필요한 최소 전류와 소비 전력을 기존의 드라이브 라인에 비하여 약 3배 감소시킬 수 있었으며, 드라이브 라인을 묻지 않고, 화소를 덮는 반사막(드라이브 라인)의 면적을 크게 하여 광효율을 2.2배 증가시키고, 제조공정을 대폭 단순화시킬 수 있는 드라이브 라인의 형상을 제시했다.

• Journal of information and communication convergence engineering
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• 제13권4호
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• pp.280-285
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• 2015

Double random phase encryption (DRPE) is one of the well-known optical encryption techniques, and many techniques with DRPE have been developed for information security. However, most of these techniques may not solve the fundamental security problem caused by using fixed phase masks for DRPE. Therefore, in this paper, we propose a key phase mask updating scheme for DRPE to improve its security, where a spatial light modulator (SLM) is used to implement key phase mask updating. In the proposed scheme, updated key data are obtained by using previous image data and the first phase mask used in encryption. The SLM with the updated key is used as the second phase mask for encryption. We provide a detailed description of the method of encryption and decryption for a DRPE system using the proposed key updating scheme, and simulation results are also shown to verify that the proposed key updating scheme can enhance the security of the original DRPE.

• Journal of Magnetics
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• 제11권3호
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• pp.143-146
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• 2006

We attempted to fabricate a new type of magneto optic spatial light modulator (MO-SLM) for multiple-tone modulation by using in-plane magnetization. In the MO-SLM, magnetic property of magneto-optical layer was modified to be suitable for multiple-tone expression by substituting Al in Bi:YIG film. At a driving current to 28 mA in an electrode of the fabricated MO-SLM, changes in brightness of pixels were observed using a polarization microscope.

• Current Optics and Photonics
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• 제3권3호
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• pp.215-219
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• 2019

Chromatic aberrations induced by Risley prisms made of a single material can be substantially compensated using a liquid crystal spatial light modulator while still keeping the prism pairs compact, simple and lightweight. A ${\pm}10^{\circ}$ optical scanning imaging system with ${\pm}2^{\circ}$instantaneous field based on LC-SLM correction is designed as an example. The ultimate simulation results show that this kind of scheme is an effective way of improving imaging performance dynamically across the full field of scanning.

• Journal of Magnetics
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• 제8권1호
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• pp.50-59
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• 2003

Spatial light modulators (SLMs) are centrally important devices in volumetric recording, data Processing, Pattern recognition and other optical systems. Various types of reusable SLMs with two-dimensional pixel arrays have been intensively developed. Of these, magneto-optic spatial light modulators (MOSLMs) have advantages of high switching speed, robustness, nonvolatility, and radioactive resistance. In this article, we review recent development work on MOSLMs, mainly in relation to our own studies.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.140-148
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• 2000

In this paper, using surface micromachining technology with thick photoresist and aluminum, an SLM(Spatial Light Modulator), which is applied to the fields of adaptive optics and pattern recognition system, was fabricated and the electromechanical properties of the fabricated micro SLM are measured. In order to maximize fill-factor and remove mechanical coupling between micro SLM actuators, the micro SLM is composed of three aluminum layers so that spring structure and upper electrode are placed beneath the mirror plate, and $10\times10$ each mirror plate is individually actuated. Also, the micro SLM was designed to be able to modulate phase and amplitude of incoming light in order to have a continuity of phase modulation of incoming light. In the case of amplitude and phase modulation, maximum vertical displacement is 4$\mum$, and maximum angular displacement is $\pm4.6^{\corc}$ respectively. The height difference of the fabricated mirror plate was able to be reduced to 1100A with mirror plate planarization method using negative photoresist(AZ5214). The electromechanical properties of the fabricated micro SLM were measured with the optical measurement system using He-Ne laser and PSD(position sensitive device).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.939-942
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• 2002

The optically addressed and electrically addressed spatial phase only light modulators without pixelized structures have been developed. A sufficient phase modulation capability and a high diffraction efficiency of these devices are useful for practical applications.