甲基红染料掺杂的聚乙烯醇薄膜光存储特性的实验研究

用2倍频小型YAG激光(532nm)作为写入光和擦除光,用He-Ne激光器623.8nm线作为读出光,用CCD作为探测器,研究了不同写入光功率下,甲基红/聚乙烯醇(MR/PVA)薄膜光栅生长的动力学过程和不同擦除光功率下,光栅擦除的动力学过程.结合光栅生长曲线的波动现象,对光存储机制进行了新的探讨.实验发现,两写入光和读出光的功率配比为1:1:1时,可获得最大衍射效率,提出读出光对写入过程具有双重作用的物理模型,对此实验结果给出了合理的解释.     

新型聚偶氮苯取向增强光折变效应及全息存储

合成了新型偶氮分子偶氮二苯胺ADPA(Azo-diphenylamine),将其掺入聚乙烯咔唑Poly(N-Vinylcarba-zole)(PVK)和聚丙烯丁酯(Poly-butylacrylate)(PBA)的聚合物(PVK-PBA)以及三硝基芴酮2,4,7-trinitro-9-flu-orenone(TNF)聚合制成薄膜器件。结果表明掺杂偶氮苯聚合物薄膜在非共振吸收下具有强的光致取向增强光折变效应。光致折射率变化值Δn达到1.3×10-3以上。样品在两相干光束作用下,可建立光折射率光栅,其衍射效率可超过30%,实现了光全息存储。讨论了影响折射率光栅的因素,并对全息存储相关结果形成的机制进行了分析。     

超分辨近场结构的研究进展及其应用

超分辨近场结构(super-resolution near-field structure,super-RENS)由于突破了传统远场光学衍射极限的限制,在纳米光储存、微纳米加工、基于局域表面等离子体增强的生物传感器方面展现出良好的应用前景,因此吸引了众多研究者的目光.文章简要介绍了超分辨近场结构的发展历程、相应的工作机理、最新研究动态及其在超高密度光存储、近场光刻中的应用状况,并对未来的工作重点做出展望.     

A virtual optical probe based on evanescent wave interference

A virtual probe is a novel immaterial tip based on the near-field evanescent wave interference and small aperture diffraction, which can be used in near-field high-density optical data storage, nano-lithography, near-field optical imaging and spectral detection, near-field optical manipulation of nano-scale specimen, etc. In this paper, the formation mechanism of the virtual probe is analysed, the evanescent wave interference discussed theoretically, and the sidelobe suppression by small aperture is simulated by the three-dimensional finite-difference time-domain method. The simulation results of the optical distribution of the near-field virtual probe reveal that the transmission efficiency of the virtual probe is 10²－10⁴ times higher than that of the nano-aperture metal-coated fibre probe widely used in near-field optical systems. The full width at half maximum of the peak, in other words, the size of virtual probe, is constant whatever the distance in a certain range so that the critical nano-separation control in the near-field system can be relaxed. We give an example of the application of the virtual probe in ultrahigh-density optical data storage.     

二元光学元件衍射效率的逐层分析法研究

提出了一种有效的分析二元光学元件衍射效率的新方法－逐层分析法，并对四台阶二元器件，就蚀刻深度误差和横向对准误差对器件衍射效率的影响进行了详细的分析和讨论，证明了用该方法分析含有横向对准误差的二元光学元件的衍射效率非常简便有效。     

全息聚合物弥散液晶材料衍射特性的优化

研究了影响全息聚合物弥散液晶(HPDLC)衍射效率的主要因素，分析了衍射效率与聚合物单体的选择、曝光强度、曝光时间、液晶含量及温度的依赖关系，从而找到最佳条件，使衍射特性得到优化.目前测得的最大衍射效率为802%.实验中还研究了扫描电镜(SEM)观察下HPDLC的表面形貌.     

固体浸没透镜光存储的信号探测技术

信号探测是固体浸没透镜成为实用存储技术的一个必需的组成部分。对在该项研究中获得的理论和实验成果进行了介绍。总结了针对固体浸没透镜机理的三维矢量理论 ,对影响信号探测的因素 ,例如头盘间距、盘片结构和光的偏振态等进行了讨论。介绍了基于固体浸没透镜光存储中信号探测的新技术和重要的实验结果。     

Resonant domain photorefractive structure in the liquid crystal-photoconducting orienting layer system

Photorefractive properties of nematic liquid-crystal cells with photoconductive orienting layers are investigated. A new mechanism is proposed based on the resonant interaction of transition and quasi-stationary domain structures with the optical interference field. A two-order-of-magnitude increase in the diffraction efficiency of gratings under resonant conditions is obtained.     

一种新型数字化衍射光变图像的存贮系统

研制了一种新型数字化衍射光变图像的存储系统。采用SLM作为自动文字输入,由消像差的远心缩微光路缩小输入文字,每个输入文字均由光栅干涉头进行调制,从而形成用于光信息存储的干涉光场,改变调制光栅的取向和条纹间隔,将改变存储文字的衍射特性。在光刻胶干版上的存储实验表明,存储的最小衍射文字尺寸可达40μm,单通道存储达3.7×104bits/cm2,而且存储的信息可以复制。     

红外混合光学系统衍射效率的测量方法及其实现

简要介绍了二元光学器件衍射效率的理论计算方法,给出了一些衍射效率的测量方法,在此基础上设计了一套实用的衍射效率测试系统,并针对一个应用在3~5μm波段的具体红外混合光学系统进行了测试,给出了测试结果,此测试系统对红外混合光学系统的设计加工具有实际意义。     

多层衍射光学元件设计原理与衍射效率的研究

叙述了多层衍射光学元件的设计原理.通过对多层衍射光学元件结构、位相延迟表达式、材料选择匹配的研究,使得优化最大光栅高度后的多层衍射光学元件能够实现大幅度提高宽光谱范围内衍射效率的作用.其衍射效率在从g谱线（435.834 3 nm）到C谱线（656.272 5 nm）的可见光范围内的任何波长上的理论衍射效率均在99％以上,带宽积分平均衍射效率为99.7％,能够满足高质量成像光学系统应用的需要,并利用该元件设计了长焦距复消色差物镜.     

Holographic data storage in a DX-center material

We report on the optical storage of digital data in a semiconductor sample containing DX centers. The diffraction efficiency and the bit-error-rate performance of multiplexed data images are shown to agree well with a simple model of the material. Uniform storage without an exposure schedule is demonstrated. The volume sensitivity is found to be ~10(3) times that of LiNBO(3):Fe. The importance of coherent addition of scattered light with diffracted light in holographic data storage is discussed.     

吖啶橙敏化的光致聚合物及其数字全息存储研究

制备了一种吖啶橙敏化的光致聚合物材料,并研究了材料的全息特性.用Ar+激光器三种波长的光对材料进行记录.结果表明,该材料具有较高的衍射效率、较高的曝光灵敏度和较大的折射率调制度,最大衍射效率均大于40%.将计算机二进制文件经过编码生成的二值图像存入样品,其再现图像较为清晰,译码后能够准确地还原出原文,表明该光致聚合物适合数字全息存储.     

非水溶性红敏光致聚合物全息性能的改善及其应用研究

为使非水溶性红敏光致聚合物材料的全息性能得到改善,采用复合光敏增感、复合引发和复合单体的方法反复对比实验,改善后体系的灵敏度为0.02 cm2/mJ,衍射效率高达83%,计算得到材料的最大折射率调制度为4.1×10-3.实验结果和理论分析表明,利用该材料制作的新型全息光栅具有损耗低、通道宽度窄、衍射效率高等优点,适于制作光通信中的波分复用器及各种光学元件.     

超短激光脉冲对宽带光学物质的微加工

通过讨论超快飞秒激光脉冲和长脉冲宽度的激光脉冲紧导致宽能隙透明电介质的损伤机理和比较超短激光脉冲与长激光脉冲对宽能隙透明电介质的损伤程度，得出超短激光脉冲是一种可对透明宽带电介质进行加工的有效工具的结论。当波长为800nm，脉冲宽度为150fs的激光脉冲紧聚焦到不同的宽能隙透明电介质（K9玻璃和ZK6玻璃）体内时，可制作不同光栅常数的光栅，并在波长为635nm的He-Ne连续激光的垂直照射下，对光栅的远场相对衍射效率和光栅的衍射效率进行了测量。     

偶氮苯液晶薄膜相位共轭的光学记录研究

利用间并四波混频研究了一种偶氮苯液昌聚合物的相位共轭和光学记录特性，在近共振条件下，用低功率Ｎｄ：ＹＡＧ倍频激光得到高效率的相位共轭光和高阶衍射光，当光强达到１０Ｗ／ｃｍ＾２量级时，薄膜显示出光记录效应，即在撒掉写入光之后，相位共轭波并不消失，进一步大光强到１０＾３Ｗ／ｃｍ＾２量级时，出现三组分别只与前向泵浦光，后向泵浦光和信号有关的高阶衍射光。其中观察到第三阶衍射光，且在撒掉任两束光后，所剩一束     

衍射光学元件衍射效率影响混合光学系统性能的一种分析方法

本文从衍射光学元件的衍射效率入手,详细地分析了衍射光学元件衍射效率同混合光学系统光学传递函数的关系,并通过一个实际例子对所分析的结果进行了深入讨论.     

Forced oscillator model of dynamic spatial charge field in the reduced Zn:Fe:LiNbO3 crystal

Holographic data storage is promised to be the next-generation optical storage technology for many years. The Zn:Fe:LiNbO₃ crystal is studied widely because of its promising holographic storage properties. The forced oscillator model is used to explain the self-erasing phenomenon in the reduced Zn:Fe:LiNbO₃ crystals. It is showed that the total spatial charge field is dominated by two kinds of carrier with different respond time, which are electron and hole, respectively. The cooperative action of two kinds carrier induces that the total charge field non-monotonically varies with the recording time. The same diffraction efficiency of hologram with equal exposure energy is realized by the self-erasing property. The precision of the optical correlation recognition based on holographic storage will be improved.     

光色效应(Fe,Mn)\:LiNbO3晶体非挥发性全息存储中自衍射效应的实验研究

在双掺杂 (Fe ,Mn)…LiNbO3 晶体光色效应非挥发性全息存储实验中 ,观测到光束耦合作用导致的自增强和自衰减效应。根据这种自衍射效应 ,归纳了四种记录和光固定实验组合方案。实验结果表明 ,在记录和光固定过程中利用自增强效应得到的最高衍射效率为利用自衰减效应得到的衍射效率的两倍左右 ,说明在实际应用中必须考虑和利用自增强效应。     

Optical Storage in Side-Chain Liquid Crystalline Polyesters

Long-term, high resolution holographic storage has been achieved in side-chain liquid crystalline polyesters with high diffraction efficiency. The information can be completely erased by heating the film to about 80°C. The modular architecture of the polyesters permits a varition in the length of the main- and side-chains and the substituents of the azo chromophore. Each of these has a profound influence on the storage properties of the polyesters. In this article, we examine the influence of the length of the side-chains, the probe-beam-polarization dependence of the observed signal on the interface and the crystalline vs. amorphous nature of the films for optical storage.