Experimental investigation of parallel optical data storage using pyrrylfulgide photochromic material

The optical storage characteristics of a new kind of organic photochromic material棗pyrrylfulgide were experimentally investigated in the established parallel optical data storage system. Using the pyrrylfulgide/PMMA film as a photon-mode recording medium, micro-images and encoded binary digital data were recorded, readout and erased in this parallel system. The storage density currently reaches 3?107 bit/cm2. The recorded information on the film can be kept for years in darkness at room temperature.     

Holographic three-dimensional telepresence using large-area photorefractive polymer

Holography is a technique that is used to display objects or scenes in three dimensions. Such three-dimensional (3D) images, or holograms, can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. The concept of 3D telepresence, a real-time dynamic hologram depicting a scene occurring in a different location, has attracted considerable public interest since it was depicted in the original Star Wars film in 1977. However, the lack of sufficient computational power to produce realistic computer-generated holograms and the absence of large-area and dynamically updatable holographic recording media have prevented realization of the concept. Here we use a holographic stereographic technique and a photorefractive polymer material as the recording medium to demonstrate a holographic display that can refresh images every two seconds. A 50?Hz nanosecond pulsed laser is used to write the holographic pixels. Multicoloured holographic 3D images are produced by using angular multiplexing, and the full parallax display employs spatial multiplexing. 3D telepresence is demonstrated by taking multiple images from one location and transmitting the information via Ethernet to another location where the hologram is printed with the quasi-real-time dynamic 3D display. Further improvements could bring applications in telemedicine, prototyping, advertising, updatable 3D maps and entertainment.     

Near-infrared sensitivity enhancement of photorefractive polymer composites by pre-illumination

Among the various applications for reversible holographic storage media, a particularly interesting one is time-gated holographic imaging (TGHI). This technique could provide a noninvasive medical diagnosis tool, related to optical coherence tomography. In this technique, biological samples are illuminated within their transparency window with near-infrared light, and information about subsurface features is obtained by a detection method that distinguishes between reflected photons originating from a certain depth and those scattered from various depths. Such an application requires reversible holographic storage media with very high sensitivity in the near-infrared. Photorefractive materials, in particular certain amorphous organic systems, are in principle promising candidate media, but their sensitivity has so far been too low, mainly owing to their long response times in the near-infrared. Here we introduce an organic photorefractive material -- a composite based on the poly(arylene vinylene) copolymer TPD-PPV -- that exhibits favourable near-infrared characteristics. We show that pre-illumination of this material at a shorter wavelength before holographic recording improves the response time by a factor of 40. This process was found to be reversible. We demonstrate multiple holographic recording with this technique at video rate under practical conditions.     

激光技术在信息存储中的应用

本文结合只读式光盘、一次写入型光盘、可擦重写光盘的读写原理讨论了激光技术在信息存储技术的应用。     

体全息光存储高速存储通道设计中的关键技术研究

一种新型的三维存储技术——体全息存储技术具有存储容量大、数据传输速率高及内容寻址等功能，具有极强的市场竞争力．本文对适用于体全息光存储器的高速存取通道的设计进行了详细论述，然后，给出了高速通道的硬件和通信程序的设计实现方法。     

Bleaching effect and nonvolatile holographic storage in doubly doped LiNbO<Subscript>3</Subscript>:Fe:Cu crystals

The bleaching effect, i. e. the crystal shows that decoloration after it is illuminated by ultraviolet light, has been observed in congruent LiNbO3:Fe :Cu crystals. Based on this bleaching effect, a new technique including the reco rding phase by two interfering red beams and fixing phase by both UV light and a coherent red beam has been experimentally investigated to realize nonvolatile holographic storage in LiNbO3:Fe:Cu. The results of proof-of-concept experiments confirm that bleaching effect becomes an alternative physical mechanism for nonv olatile holographic storage with high recording sensitivity and weak light-induced scattering noise.     

三维光数据存储的分析与计算

三维多层光折射数字存储是一种新型的高密存储技术,对于克服目前的光存储系统的容量限制具有很大的潜力。文章用埃瓦得球结构分析了此种存储方法的横向与纵向带宽,从而在空域内计算了存储的密度。存储容量可以达到1Tb/cm3,用于光通信系统中是可行的;根据该存储系统在更深层聚焦时产生的球差,提出了一种全息校正装置。     

Miniaturized volume holographic optical data storage and correlation system with a storage density of 10 Gb／cm^3

The general idea of holographic optical data storage (HODS) is briefly introduced. Based on the recent advances of HODS, the key techniques and the challenges of HODS are discussed. Some new techniques are proposed to improve the system. A miniaturized volume holographic data storage and correlation system is presented. It can achieve a density of 10 Gb/cm^3 and a fast correlation recognition rate of more than 2000 images per second. It shows the attracting potential advantages over other conventional storage methods in the information storage as well as information processing.     

Fe:LiNbO3晶体角度复用全息实验研究

研究了以掺铁铌酸锂(Fe∶LiNbO_3)晶体为记录介质的光折变体的全息记录和读出特性.搭建了角度复用光折变体全息记录的实验光路,记录了光折变全息图.实验研究了Fe∶LiNbO_3晶体的响应灵敏度,测量了光折变体全息记录和读出的衍射效率,测量了最小角度复用间隔,实验结果有助于评估和优化角度复用全息图的容量.     

PMMA/TiO2纳米复合粒子的制备及初步应用研究

采用原位乳液聚合法，用经硅烷偶联剂处理过的纳米TiO₂，与MMA单体混合，合成PMMA/TiO₂纳米复合粒子。探讨了TiO₂表面改性机理， 并用TG、IR、DSC等对产物进行了表征，表明纳米TiO₂被包覆在聚合物PMMA中。将复合粒子加入紫外光固化涂料，制得复合涂膜。由原子力显微镜照片分析，制备的PMMA/ TiO₂复合粒子平均粒径约为75nm。分别在涂膜中添加等量的纳米TiO₂和PMMA/ TiO₂纳米复合粒子，制成两张复合涂膜，比较发现PMMA/ TiO₂纳米复合粒子在涂膜中的分散情况优于纳米TiO₂，呈现良好的纳米级分散，明显改善了TiO₂与涂膜的相容性，从而提高了涂膜的硬度及涂膜与基材的附着力。     

对一种新型全有机复合薄膜的超高密度信息存储研究

用真空热壁法生长了一种新型全有机复合薄膜TTF/m-NBP(tetrathiofulvalene/m-nitrobenzylidene propanedinitrile)。用透射电子显微镜和傅立叶变换红外光谱对薄膜的表征结果证明,该制备方法能够生长出较大面积的化学结构完善的单晶薄膜。用原子力显微镜(AFM)和扫描隧道显微镜(STM)都观察到了TTF/m-NBP薄膜表面的原子级分辨像。通过STM针尖施加脉冲电压在TTF/m-NBP薄膜上实现了纳米级的信息存储,最小记录点直径约为1.2nm。扫描隧道谱分析表明TTF/m-NBP薄膜具有很好的电开关“记忆”特性。初步研究认为其电开关机制可能主要是脉冲电压诱发的TTF电子给体与m-NBP电子受体分子间的电荷转移的变化所致。     

基于PAL的图像数据存储技术研究

针对弹载图像采集系统设计中存在无法准确稳定存储高速数据流,而导致图像信息记录和存储的可靠性严重降低的问题,设计了一种基于PAL制图像数据的无延时存储方法。通过采用乒乓缓存设计和流水线结构方式,解决了高速图像数据输出和串口Flash存储器的低写入速度不匹配的问题。通过实验分析验证,设计能够解决高低速存储介质中速度匹配问题,实现对高速图像数据的精确存储和记录,为后期图像恢复提供了可靠的数据。     

全息术的新进展

近年来，全息术在制造方法和应用领域取得了一系列突破性进展，使得全息术重新成为世界各国关注的一个研究热点．在简要回顾半个世纪全息术发展历史的基础上，重点介绍了近十多年来全息术领域中比较有影响的研究成果，展望了全息术的未来发展方向．     

感光材料灵敏度表示方法的讨论

讨论了感光特性曲线的线性区表示感光灵敏度的各种方法，提出将√η－Ｈ曲线或√η－Ｖ曲线线性区衍射效率最大的点作为灵敏度点，可以最佳确定全息记录材料对光的敏感能力。     

iSCSI带外虚拟化的研究与实现

研究了基于因特网小型计算机系统接口(iSCSI)带外方式的存储虚拟化模型,提出了一种iSCSI带外存储虚拟化的体系结构及命令流程．根据该体系结构,实现了基于iSCSI带外存储虚拟化的存储系统,并对该实现在低级别RAID下进行了读／写性能测试．结果表明,读／写性能随着传输数据块的变大而上升,当数据块的大小达到64 Kbyte时,RAID0的读/写和RAID1的读,其性能已接近30 Mbyte／s．     

Optical data storage in nonphotosensitive media by femtosecond laser pulses

Ultrashort lasers have become powerful tools by inducing extremely nonlinear effects in a wide variety of materials. Femtosecond laser data storage in non-photosensitive media is promising for its high density and fast retrieval. We reviewed the progress of three types of femtosecond laser storage in transparent materials: three-dimensional bit-oriented storage by micro-voids, holographic data storage by two beam interference and storage by computer-generated holograms.     

Optical data storage in nonphotosensitive media by femtosecond laser pulses

Ultrashort lasers have become powerful tools by inducing extremely nonlinear effects in a wide variety of materials. Femtosecond laser data storage in non-photosensitive media is promising for its high density and fast retrieval.We reviewed the progress of three types of femtosecond laser storage in transparent materials:three-dimensional bit-oriented storage by micro-voids,holographic data storage by two beam interference and storage by computer-generated holograms.     

An updatable holographic three-dimensional display

Holographic three-dimensional (3D) displays provide realistic images without the need for special eyewear, making them valuable tools for applications that require situational awareness, such as medical, industrial and military imaging. Currently commercially available holographic 3D displays use photopolymers that lack image-updating capability, resulting in restricted use and high cost. Photorefractive polymers are dynamic holographic recording materials that allow updating of images and have a wide range of applications, including optical correlation, imaging through scattering media and optical communication. To be suitable for 3D displays, photorefractive polymers need to have nearly 100% diffraction efficiency, fast writing time, hours of image persistence, rapid erasure, and large area-a combination of properties that has not been shown before. Here, we report an updatable holographic 3D display based on photorefractive polymers with such properties, capable of recording and displaying new images every few minutes. This is the largest photorefractive 3D display to date (4 x 4 inches in size); it can be recorded within a few minutes, viewed for several hours without the need for refreshing, and can be completely erased and updated with new images when desired.     

Enhanced resistive switching properties of HfAlOx/ZrO2- based RRAM devices

Resistive Random-Access Memory (RRAM) devices are recognized as potential candidates for next-generation memory devices, due to their smallest cell size, high write/erase speed, and endurance. Particularly, the resistive switching (RS) characteristics in oxide materials have offered new opportunities for developing CMOS-compatible high-density RRAM devices. In this study, the RS behavior of HfAlO_x/ZrO₂ thin films sandwiched structure between TiN bottom electrode and Au top electrodes were investigated. It was found that Au/HfAlO_x/ZrO₂/TiN stacks were superior in terms of RS performance when compare to Au/HfAlO_x/TiN memory stacks. The devices demonstrated a good resistance ratio of high resistance state and low resistance state ～10³ for Au/HfAlO_x/TiN and ～10⁵ for Au/HfAlO_x/ZrO₂/TiN stacks, respectively. Both stacks showed good retention characteristics (>10⁴ ?s) and endurance (>10³ cycles). The experimental current-voltage characteristics fitted with different conducting mechanisms, the linear lower bias region is dominated by ohmic conductivity, whereas the non-linear higher bias region was dominated by space-charge limited current conduction mechanism.     

全息光学元件(HOE)用于光盘读写头设计

讨论了在光盘读写头设计中采用全息光学元件(HOE)及二极管激光器所涉及的技术问题及解决方法。双全息光学元件的应用可以校正二极管激光器输出的椭圆光束,可以补偿二极管激光输出波长变动对聚焦光斑的影响。采用光线追迹计算机模拟方法讨论了几种全息式光盘读写头结构。对双球面透镜双全息光学元件的读写头结构给出了实验结果。