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Pacific Rim conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： S. Shinada F. Koyama K. Suzuki N. Nishiyama K. Goto K. Iga Tokyo Institute of Technology Yokohama Japan Tokai University Numazu Shizuoka Japan

An ultra-high density optical memory using near field optics has been attracting much interest for future data storage. Betzig and coworkers (1992) demonstrated optical recording by an optical scanning microscope (NSOM) and suggested the possibility of tera byte data storage. One of the authors (K. Goto) proposed (1998) a tera byte optical memory system using a VCSEL array. One of the key issues in the proposed optical disk system is to realize an optical head consisting of a 2-dimensional VCSEL array. In near-field optics memory, there still remains the difficulty in getting a high output power efficiently from a sub-wavelength sized aperture. It is especially important to realize a high efficiency VCSEL for optical heads by reducing the total power consumption in arrays. We proposed a metal aperture VCSEL for producing near field light with high efficiency. In the study, we carried out a near field analysis of a micro-aperture VCSEL and present some basic process technologies for realizing the proposed device.

关键词： Surface emitting lasers Stimulated emission optical recording optical arrays Vertical cavity surface emitting lasers Memory optical microscopy Apertures Magnetic heads Power generation

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Improvement to holographic data storage using optimized phase mask

Improvement to holographic data storage using optimized phas...

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Pacific Rim conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： You-Seok Bae Jianwen Yang Sang-II Jin Soo-Young Lee Cheol-Hoon Park Department of Electrical Engineering Korea Advanced Institute of Science and Technology Taejon South Korea Korea Advanced Institute of Science and Technology Daejeon Daejeon KR

Holographic data storage has the advantages of high parallelism, fast access, and large capacity. The storage capacity is represented by the stored pages and pixels in each page. Due to the 3-D nature of the holographic medium, many pages of data may be multiplexed by various methods. For optimal use of the dynamic range of the medium, various phase masks are used to uniform the Fourier spectrum. The design of these masks is based on statistical properties of the input pixels. But, the interpixel cross talk, which is dominated by the pixels within the same page, is difficult to reduce owing to the diffraction of the limited aperture size of the medium. In the paper, we expect the spectrum to be uniform and the reconstruction error to be minimal simultaneously. Therefore, we set the targets of the spectral distribution to be constant /spl rho//sub f/ and the reconstructed amplitude /spl rho//sub 2/ equal to the input /spl rho//sub 1/. The desired /spl rho//sub f/ should be chosen so that the energy of the spectral plane would be equal to that of the input plane. We can get the transform matrix between input and Fourier plane and between input and output.

关键词： Holography Memory optical distortion optical recording Optimized production technology optical diffraction Energy efficiency Phase modulation optical modulation Pattern matching

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data reduction for optical 3D-inspection in automotive application

Data reduction for optical 3D-inspection in automotive appli...

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International conference on Multisensor Fusion and Integration for Intelligent Systems (MFI)

作者： R. Dillmann S. Vogt A. Zilker Institute of Process Control and Robotics University of Karlsruhe Karlsruhe Germany Research and Technology DaimlerChrysler Aerospace Ulm Germany

advances in optical sensors, computer graphics, and robotics provide new technology for the processes in styling, design, and quality management. They are used in optical inspection and reverse engineering to speed up the development process. One of the challenges of these new technologies for Daimler-Chrysler is the coupling to current CAD systems. The 3D data obtained from fast optical sensors have to be post-processed before they can be transferred to a commercial computer aided design system due to data format and the amount of the measured data. Reducing the measured data can remove important information or lower the accuracy of the data. This paper describes current and two new reduction algorithms for optical 3D data. It illustrates the need of data reduction in an application: a historic Mercedes Benz racing car is measured by a optical sensor delivering 98.3 million points. They are reduced down to 1 million points for reverse engineering of the car body surface.

关键词： Automotive applications optical sensors optical design Reverse engineering Computer graphics Robot sensing systems Process design Quality management Inspection Design automation

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Development of a COTS mass storage unit for the space readiness coherent lidar experiment

Development of a COTS mass storage unit for the space readin...

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conference on Digital Avionics Systems (DASC)

作者： K. Liggin Computer and Data Systems Group Avionics Laboratory NASA Marshall Space Flight Center Huntsville AL USA

The technology to develop a Mass storage Unit (MSU) using commercial-off-theshelf (COTS) hard drives is an on-going challenge to meet the Space Readiness Coherent Lidar Experiment (SPARCLE) program requirements. A conceptual view of SPARCLE's laser collecting atmospheric data from the shuttle is shown. The determination to develop this technology required several in depth studies before an actual COTS hard drive was selected to continue this effort. It is suggested that continuing the development of the MSU can, and will, serve future NASA programs that require larger data storage and more on-board processing. This effort will provide a greater means to other programs that have limited downlink capabilities within their payload telemetry streams.

关键词： Laser radar Space technology Aerospace electronics Space shuttles Frequency Sampling methods NASA Atmospheric measurements optical control Bandwidth

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Hard disk drive read channels: technology and trends

Proceedings of the Custom Integrated Circuits Conference

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Proceedings of the Custom Integrated Circuits conference 1999年 309-316页

作者： Thapar, Hemant Lee, Sang-Soo Conroy, Cormac Contreras, Richard Yeung, Alfred Chern, Jenn-Gang Pan, Tzuwang Shih, Shih-Ming DataPath Systems Inc Los Gatos CA United States

ISBN: (纸本)0780354443

advances in read channel technology over the past 8 years have contributed approximately 50% to the areal density growth in magnetic hard disk drive (HDD) systems. This paper provides an overview of HDD read channel technology and trends. Dominant channel impairments are discussed along with signal processing methods to mitigate their effects. Equalization and coding techniques, capable of achieving higher areal densities, are reviewed. Finally, circuit design challenges in meeting the emerging data rate requirement of 1 Gb/s in read channel products are discussed.

关键词： Hard disk storage

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A 100 MHz synchronized OEIC photoreceiver in n-well, CMOS technology

A 100 MHz synchronized OEIC photoreceiver in n-well, CMOS te...

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conference on Optoelectronic and Microelectronic Materials and Devices

作者： K. Ayadi P. Danielsen COM center Technical University of Denmark Lyngby Denmark

We analyze and demonstrate a synchronized CMOS photoreceiver for the conversion of optical inputs of pulse-light to electronic digital signals. Small-signal and photonic analysis of the proposed circuit are detailed. The photoreceiver was operated at 100 MHz with only 13.3 fJ/pulse of 830-nm input light. Its effective area is 100/spl times/60 /spl mu/m/sup 2/ which makes this monolithic photoreceiver extremely important for use in data storage and optical interconnection applications.

关键词： CMOS technology Optoelectronic devices Synchronization Circuits Clocks Voltage optical pulses Capacitance Signal analysis optical interconnections

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高密度光学信息存储的最新进展

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光电子技术与信息 1999年第4期12卷 7-13,20页

作者：王薇薇明海中国科学技术大学物理系合肥230026

本文介绍高密度光信息存储的最新进展，阐述在光折变材料上全息存储的多波长、多角度、多相位记录和读取方法，噪声的改善和全息图的寿命；双光子吸收在聚焦光束扫描存储技术中的应用；近场光学记录方法，光纤探针的研制以及孔径介质... 详细信息

本文介绍高密度光信息存储的最新进展，阐述在光折变材料上全息存储的多波长、多角度、多相位记录和读取方法，噪声的改善和全息图的寿命；双光子吸收在聚焦光束扫描存储技术中的应用；近场光学记录方法，光纤探针的研制以及孔径介质间距控制。最后讨论了光存储材料的发展。

关键词：全息存储双光子吸收近场光学记录

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Two color hologram storage using stoichiometric lithium niobate

Two color hologram storage using stoichiometric lithium niob...

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Pacific Rim conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： K. Kitamura Y. Furukawa M. Lee H. Hatano R. Macfarlane National Institute for Research in Inorganic Materials Tsukuba Japan IBM Almaden Research Center San Jose CA

Digital holographic memory using photorefractive material is one of the most promising candidates for the next-generation of data storage, which simultaneously provides high capacity, fast transfer rate and short access time. This comes from a three-dimensional volume holographic multiplexing scheme based on two dimensional page oriented read-write mechanisms. However there are numerous hurdles on the road to success. The development of a really satisfactory recording material for holographic data storage applications remains perhaps most important barrier to practical implementation of the technology. The ideal material must simultaneously possess many properties such as good sensitivity, large dynamic range, long data retention times and excellent optical quality. In addition, it must be able to be mass produced. From the above points of view, lithium niobate (LiNbO/sub 3/; abbreviated as LN) is the most promising candidate among all the inorganic photorefractive materials. High quality crystals of up to 3 inches (recently 4 inches) diameter of LN are commercially produced by the Czochralski method as substrate material of SAW devices. Because the growth method has been established, LiNbO/sub 3/ single crystals doped with hundred wt. ppm of Fe have been investigated as photorefractive data storage material. However, the photorefractive properties are not sufficient for applications and further improvements, especially in writing speed is required as a high priority.

关键词： Lithium niobate Holography Photorefractive materials Memory optical recording optical materials Crystals Crystalline materials Photorefractive effect Roads

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Two-photon polymerization initiators for efficient three-dimensional optical data storage and microfabrication

Two-photon polymerization initiators for efficient three-dim...

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conference on Lasers and Electro-Optics (CLEO)

作者： S.M. Kuebler S. Ananthavel M. Rumi S.R. Marder J.W. Perry S. Barlow B.H. Cumpston D.L. Dyer J.E. Ehrlich L.L. Erskine A.A. Heikal I.-Y.S. Lee D. McCord-Maughon Jinqui Qin H. Rockel Xiang-Li Wu Dept. of Chem. Arizona Univ. Tucson AZ USA Beckman Institute and Division of Chemistry an Chemical Engineering California Institute of Technology Pasadena CA USA Department of Chemistry University of Arizona Tucson Tucson AZ USA

Summary form only given. Two-photon excitation provides a means of activating chemical or physical processes with high spatial resolution in three dimensions and has enabled the development of 3D fluorescence imaging, 3D optical data storage, and 3D lithographic microfabrication. Each of these applications takes advantage of the fact that the two-photon absorption probability depends quadratically on intensity, and therefore under tight-focusing conditions, the absorption is confined at the focus to a volume of order /spl lambda//sup 3/, where /spl lambda/ is the laser wavelength. Any subsequent process, such as fluorescence or a photo-induced chemical reaction, is also localized in this small volume. For instance, two-photon excitation can initiate conventional reactions such as side-group deprotection, radical generation, and polymerization, through energy transfer or electron transfer. However, the efficiency of such processes depends critically on the strength of the chromophore's two-photon absorptivity. We have developed a wide array of chromophores which hold great promise for 3D optical data storage and 3D microfabrication. These materials are based on donor-/spl pi/-donor, donor-acceptor-donor, or acceptor-donor-acceptor structural motifs.

关键词： Chemical processes Fluorescence optical polymers Memory Absorption optical arrays Spatial resolution High-resolution imaging optical imaging Focusing

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Quantitative velocity field measurements in reduced-gravity combustion science and fluid physics experiments

Quantitative velocity field measurements in reduced-gravity ...

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IEEE Instrumentation and Measurement technology conference

作者： P.S. Greenberg M.P. Wernet Lewis Research Center NASA Cleveland OH USA

Systems have been developed and demonstrated for performing quantitative velocity measurements in reduced-gravity combustion science and fluid physics investigations. The unique constraints and operational environments inherent to reduced-gravity experimental facilities pose special challenges to the development of hardware and software systems. Both point and planar velocimetric capabilities are described, with particular attention being given to the development of systems to support the International Space Station laboratory. Emphasis has been placed on optical methods, primarily arising from the sensitivity of the phenomena of interest to intrusive probes. Limitations on available power volume, data storage and attendant expertise have motivated the use of solid-state sources and detectors, as well as efficient analysis capabilities emphasizing interactive data display and parameter control.

关键词： Velocity measurement Performance evaluation Combustion Physics Hardware Software systems International Space Station Laboratories optical sensors Probes

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