宽场平谱面全息凹面光栅光谱仪的设计

全息凹面光栅光谱仪具有平谱面、小型化、大孔径、高分辨率等优点。首先从信息光学的角度推导了全息凹面光栅的成像公式,在垂直于狭缝和平行于狭缝的平面上系统分析了全息凹面光栅光谱仪的成像性能;在垂直于狭缝的平面上,全息凹面光栅光谱仪具有良好的平谱面性;在平行于狭缝的平面上,全息凹面光栅光谱仪克服了传统平面光栅的谱线弯曲和色畸变,实现了谱线平直成像;此外指出全息凹面光栅光谱仪固有的弧矢场曲对视场扩展的限制。然后根据理论分析结果提出了结构对称消场曲的全息凹面光栅光谱仪的设计思想,利用ZEMAX软件优化设计了像差补偿型全息凹面光栅光谱仪。在保证相对孔径F#=3、光谱分辨率为20nm/mm、空间分辨率小于25μm等技术指标不变的前提下,设计了狭缝长度为0.4mm的传统单球面镜全息凹面光栅光谱仪和狭缝长度为8mm的像差补偿型全息凹面光栅光谱仪。结果表明,改进后的像差补偿型全息凹面光栅光谱仪成功地将视场扩大为单球面镜全息凹面光栅光谱仪的20倍。     

全息光栅

<正> 法国乔皮恩·依冯公司在1967年首次研制成了全息光栅,目前仍属领先地位。该公司的最新成果是制成了TV型凹面全息光栅。这种光栅不但球差小,而且彗差和象散降低到了最小程度。例如在该公司生产的H20和HL型单色仪及喇曼分光光度计上,均用了TV型凹面全息光栅。此外,还制成了面积达135×240mm,6500条线/mm的平面全息光栅,并正在研究用紫外激光器制造优质的全息光栅。     

全息光栅的制造技术及其改进

本文叙述了全息光栅的制造原理、工艺要求和制造技术。介绍了平场全息光栅、图象全息光栅、超环面全息光栅、激光全患光栅和闪耀全息光栅的新进展。最后,作者提出进一步发展全息光栅的若干建议。     

金纳米颗粒掺杂光致聚合物的体全息混合光栅模型

金纳米颗粒掺杂光致聚合物在全息曝光过程中,光产物周期分布会形成折射率调制相位型主光栅,同时金纳米颗粒周期分布形成由局域表面等离子体共振引起强吸收的振幅型辅助光栅。研究基于耦合波理论的一种混合光栅模型,分析了光栅的体全息光学特性。结果表明,混合光栅中的折射率光栅和吸收光栅都能够提升体光栅的衍射效率; 体光栅的角度选择性也可以得到明显的改善。     

体全息成像系统中非周期体光栅的深度选择性研究

由一束球面波和一束平面波或者两束球面波干涉所形成的体全息光栅,由于其光栅矢量在全息图体积内是随位置的变化而变化的,所以被称为非周期型的体光栅。主要研究了用于体全息三维成像系统的非周期体光栅的深度选择特性。根据叠加的原理,将非周期体光栅看作多个固定周期的基元体光栅的叠加,结合耦合波理论分析非周期体光栅的衍射特性。采用这一方法,利用Matlab软件模拟,研究了两束记录光夹角对所记录的非周期体光栅深度选择性的影响和在两束记录光夹角相同时,球面参考光体全息成像系统及平面参考光体全息成像系统深度选择性的差别,最后在光折变晶体材料中进行非周期型和周期型体光栅的记录和再现,对模拟结果进行了实验验证。     

浮雕型全息相位光栅的衍射

本文从理论上推导出了浮雕型相位全息光栅所满足的衍射方程式,并数值计算了光刻胶四种情况下的+1级衍射光的衍射效率与相位光栅刻蚀深度的关系.还和大量实际拍摄的全息光栅作了比较,发现它基本上都能与实验相符；文中还指出了如何选择拍摄参数来控制光栅的刻蚀深度,以确保制作高衍射效率和高信噪比的PET(聚酯薄膜)模压全息片所需要的光刻胶母版拍摄.     

利用马赫-曾德干涉光路制作二维全息光栅

全息光栅是一种重要的分光元件,而全息光栅的制作实验也是目前国内很多高校开设的一个综合性设计性实验。利用马赫-曾德干涉光路进行全息光栅的制作。通过改变全息记录光束的夹角以及旋转全息干板进行多次曝光的方式,制作了具有不同光栅常数的二维全息光栅结构。通过光栅衍射光斑,可以验证各种二维光栅结构的存在。     

测量全息光栅光栅常数的两种简易方法

文中提出了两种利用放大原理测量全息光栅光栅常数的简单方法:扩束镜放大成像法和凸透镜放大成像法。采用这两种方法可以直接看到全息光栅的放大像,适于全息光栅结构的实验演示以及所制全息光栅质量的检查。同时这两种方法测量光栅常数具有简单、直观、准确、易于操作等优点,适合测量光栅常数大于1微米的全息光栅,并且光栅常数越大测量越精确,弥补了衍射法适于测量小光栅常数的不足。     

变波长读出条件下光折变局域体全息光栅的衍射性质

利用二维耦合波理论,研究了用短波长记录全息光栅而用通讯波段内的长波长读出时,用于90°结构垂直读出平板型的光折变局域体全息光栅的衍射性质.讨论了局域体全息光栅的几何尺寸对其衍射效率及光栅布喇格选择性的影响.结果表明,随着光栅的纵向和横向尺寸的增加,光栅的衍射效率也逐渐增加.当光栅的纵向和横向尺寸发生改变但光栅的总面积不变时,光栅衍射效率保持不变.此外,随着光栅尺寸的增加光栅的布喇格选择性越好.在利用短波长记录全息光栅而用长波长读出的光学器件设计过程中,为了获得最佳的衍射效率及其布喇格选择特性,应当根据要求合理地设计光栅的几何尺寸.     

全息离子束刻蚀衍射光栅

全息离子束刻蚀衍射光栅集中了机械刻划光栅的高效率和全息光栅的无鬼线、低杂散光、高信噪比的优点．全息离子束刻蚀已作为常规工艺手段应用于真空紫外及软x射线衍射光栅的制作．文章对全息离子束刻蚀衍射光栅的制作方法、主要类型、研究现状和应用进行了综述．     

Holographic topological semimetals

The holographic duality allows to construct and study models of strongly coupled quantum matter via dual gravitational theories.In general such models are characterized by the absence of quasiparticles, hydrodynamic behavior and Planckian dissipation times. One particular interesting class of quantum materials are ungapped topological semimetals which have many interesting properties from Hall transport to topologically protected edge states. We review the application of the holographic duality to this type of quantum matter including the construction of holographic Weyl semimetals, nodal line semimetals, quantum phase transition to trivial states(ungapped and gapped), the holographic dual of Fermi arcs and how new unexpected transport properties,such as Hall viscosities arise. The holographic models promise to lead to new insights into the properties of this type of quantum matter.     

Visualized measurement of the electric field in large aperture LiNbO3 crystal by digital holographic interferometry

The electric field distribution in Li Nb O3 crystal under different electrode shape is presented by using the digital holographic interferometry. Three configurations of phase modulator including the rectangular electrode type,single-triangle electrode type, and dual-triangle electrode type are performed in this experiment. The nonuniform electric field distribution in these phase modulators are observed and the electric field increases with voltage increasing. The digital holographic interferometry with high electro-optic effect improves the measurement precision. The digital holographic interferometry provides an effective way for studying the electric field distribution. Such in situ quantitative analysis of electric field distribution is a key to optimizing electrode shape.     

A study of preparation techniques and properties of bulk nanocomposites based on aqueous albumin dispersion

It is established that DNA films sensitized by organic dyes (for example, acridine orange), subjected to pulsed excitation in the dye absorption band, allow for several types of time-dependent holographic recording. Dynamic holographic gratings on the dye triplet states and thermal and relief-phase holographic gratings of nondestructive type have been recorded. The efficiency and lifetime of these gratings depend strongly on the concentration of dye, the type of its bonding with the biopolymer, and the recording-pulse energy. High-efficiency relief holographic gratings formed due to the structural transformations occurring in the biopolymer matrix when the energy of recording laser pulses dissipates into heat spontaneously and completely (or almost completely) disappear with time at room temperature. Some data on the distribution of acridine orange molecules over binding sites in the DNA matrix are obtained.     

复合全息透镜用作单色器

本文提出了用一个双复合重铬酸明胶全息透镜作单色器,计算并测量了此全息透镜的光谱半宽度,实验结果表明此新型单色器的可行性。     

红敏光聚合物干板的使用特性

光聚合物是一种新的光全息记录材料.本文介绍了红敏光聚合物干板在学生全息实验中的使用情况,实验测定了该干板的曝光均匀性、全息图的稳定性以及异丙醇溶液和热风吹干的作用.     

无透镜傅里叶变换型全息瞄准具研究

基于无透镜傅里叶变换全息术制作了一种新型激光全息瞄准具。瞄准具的核心部件是由一块无透镜傅里叶变换位相全息图和一块全息光束变换器组成的全息光学元件。其突出优点是大视场,大出瞳距离,适合双眼瞄准。此外,瞄准线为明亮的虚像,不会暴露目标,结构简单,对射击近距离运动目标效果突出。介绍了全息瞄准具组件的原理和制作方法,并对其性能进行了分析。     

动态微粒场诊断用全息光路的设计与分析

本文分析了动态微粒场测试的特点,设计了一种适合于动态微粒场用脉冲激光全息诊断的全息光路,并从理论上进行了分析。使用这种全息光路记录的微粒场全息图,当用记录参考光,而不是它的共轭光照明再现时,就能获得微粒的实象,因而,使得参考光类型的选择更加灵活。同时,由于光路设计上还考虑了参物光之间的空间相干性的匹配,故降低了对激光器横模的要求。     

Transmission type twisted nematic liquid crystal display for three gray-level phase-modulated holographic data storage systems

Gray-level data pages enhance the storage capacity of holographic data storage systems. A balanced three gray-scale data page in phase mode produces a homogenized Fourier spectrum which is regarded to be necessary for suitable exploitation of the holographic recording medium. A commercially available transmission type twisted nematic liquid crystal display has been characterized for use as a phase spatial light modulator with phase modulation in the range 0–3π/2 at 532 nm wavelength, such that it may be used for holographic data storage with binary as well as three gray-level phase-modulated data pages. Experimental results of the phase and amplitude modulation characteristics of the SLM, Fourier plane homogeneity, and recording of phase-modulated binary, three gray-level data pages and their reconstruction with a real-time holographic interferometric method are presented.     

Real-time image subtraction in four-wave mixing with photorefractive Bi12GeO20 crystals

Based on a classical two-exposure holographic technique, real-time image subtraction is obtained in four-wave mixing of a reflection hologram type with highly sensitive photorefractive Bi₁₂GeO₂₀ crystals. This method takes advantage of the relatively slow response and erasure times of holographic recording in Bi₁₂GeO₂₀ crystals.     

Sensitivity and optimization in the determination of deformations by holographic interferometry

The use of a fringe-counting holographic interferometric technique for measuring small superficial displacements can present difficulties in determining the measurement inaccuracy. A useful general method is given here for the analysis of errors in displacement measurements. The optimum number and type of observation directions are determined and correspond to counting in the four semi-diagonals of the holographic plate. The technique, as applied to skull experiments, makes it possible to measure directly displacements of up to 20 μm, in the object plane parallel to the holographic plate. The associated errors range from 0.1–0.3 μm, for a counting inaccuracy of of a fringe and increments of traction of 100 g to 1 kg of force.