• Electronics and Telecommunications Trends
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• v.37 no.4
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• pp.81-88
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• 2022

In this study, we investigate the trends and prospects of spatial light modulation (SLM) technology that enables full complex modulation as a next-generation SLM. Current SLM technology, which is used as a key element in holography, augmented reality (AR), XR, and realistic displays, has performance limits that modulate only amplitude or phase. Notably, SLM capable of full complex modulation does not produce diffraction noise, unlike DC and twin image, and thus has a high-efficiency performance. In the future, the application field of next-generation SLM, which can be full-complex modulated, is expected to cover a wide range of holography-AR and-XR devices, optical artificial intelligence, and 6G free space optics communications, which will greatly contribute to the development of a super-realistic metaverse platform and service.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.2
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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).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.1-10
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• 2006

In this paper, a new high resolution XGA-SLM is implemented through modification of a commercial TFT-LCD beam projector and its optical modulation characteristics as a spatial light modulator(SLM) is also analyzed. First, the optics module, projection lamp and fans are removed from a commercial beam projector and instead some electric circuits to compensate their removal are manufactured and then, by inserting them into the beam projector, a new XGA-SLM is finally implemented. Second, from some optical experimental results, this TFT-SLM is found to have a good optical linearity in amplitude and phase modulation characteristics as a function of the input gray levels. Especially, through implementation of a binary phase-type correlator such as BPEJTC by using the suggested TFT-LCD panel, the implemented SLM is proposed as a new relatively low-cost and high resolution SLM for optical information processing.

• 전자공학회논문지 IE
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• v.45 no.1
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• pp.7-14
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• 2008

In this paper, a new high resolution XGA-SLM is implemented through modification of a commercial TFT-LCD beam projector and its optical modulation characteristics as a spatial light modulator(SLM) is also analyzed. That is, the optics module, projection lamp and fans are removed from a commercial beam projector and instead, some electric circuits to compensate their removal are manufactured and then, by inserting them into the beam projector, a new XGA-SLM is finally implemented. From some characteristic experimental results of the implemented high resolution TFT-LCD SLM, the proposed TFT-SLM is found to have an good optical linearity in amplitude and phase modulation characteristics as a function of the input gray levels. Especially, through implementation of the suggested TFT-LCD panel, the implemented SLM is proposed as a new relatively low-cost and high resolution SLM for optical information processing.

• Journal of Magnetics
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• v.11 no.3
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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.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.88-93
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• 1988

For coherent optical information processing the thickness uniformity of the spatial light modulators(SLMs)is highly demanded. The liquid crystal display(LCD), which is commercialized as a pocket-sized television, is considered as one of the most cheap 2-dimensional SLM. But usually it has lack of thickness uniformity. Thus phase correction to compensate the thickness nonuniformity must be preceded before it is used as an SLM. In this paper relatively easy phase compensation method applicable to binary SLMs is discussed and experimentally verified by using the optical joint transformantion concept.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1099-1102
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• 2005

In this paper, a new visual servo method, which uses 5 axis picomotor to compensate the misalignment generated between a SLM and a CCD in a holographic storage device, was proposed and the effectiveness of it was proved by the experiment. In a holographic storage device, the data processing is done by the SLM and the CCD, and the shape of data is 2 dimensional binary patterns. Therefore, the exact image matching between the SLM and the CCD is very important, and the mismatching of it causes the errors in the data reconstruction. First, the brief introduction of a holographic data storage is given, then, BER concept which is errors caused by pixel mismatch between the SLM and the CCD is defined. Second, the geometric relation between 5 axis picomotor and the CCD movement is studied. Finally, the visual servo method using 5 axis picomotor to reduce the BER in a holographic storage device is proposed and experimented. From the experiment, we find that about 3% BER improvement is obtained by the proposed method.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.76-77
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• 2003

차세대 정보저장 기술중의 하나인 홀로그래픽 데이터 저장 기술은 빠른 데이터 접근속도와 기록 매질의 동일 위치에 수 천 페이지의 광정보를 중첩 기록할 수 있기 때문에 높은 저장용량을 갖는다. 이러한 홀로그래픽 데이터 저장을 위한 주요 구성으로 SLM(spatial light modulation)과 홀로그래픽 기록 매질을 들 수 있다. SLM은 전기적 신호를 광신호로 변조하기 위한 입력장치로 사용되며, 홀로그래픽 시스템에 사용되는 기록 매질은 고감도, 간단한 실시간 처리, 고회절효율, 기록 후 긴 안정성이 요구된다. (중략)

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.13-13
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• 2002

A Spatial light modulator (SLM) is a real-time programmable device having the modulation function of the amplitude, phase or polarization of an optical wavefront as a function of position via electrical or optical control signals. Various types of reusable SLMs with two-dimensional pixel arrays are centrally important devices in volumetric recording, data processing, pattern recognition, optical computer and other optical system. (omitted)

• Current Optics and Photonics
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• v.4 no.4
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• pp.286-292
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• 2020

Imaging through multicore fiber (MCF) is of great significance in the biomedical domain. Although several techniques have been developed to image an object from a signal passing through MCF, these methods are strongly dependent on the surroundings, such as vibration and the temperature fluctuation of the fiber's environment. In this paper, we apply a new, strong technique called deep learning to reconstruct the phase image through a MCF in which each core is multimode. To evaluate the network, we employ the binary cross-entropy as the loss function of a convolutional neural network (CNN) with improved U-net structure. The high-quality reconstruction of input objects upon spatial light modulation (SLM) can be realized from the speckle patterns of intensity that contain the information about the objects. Moreover, we study the effect of MCF length on image recovery. It is shown that the shorter the fiber, the better the imaging quality. Based on our findings, MCF may have applications in fields such as endoscopic imaging and optical communication.