我国模压全息技术发展现况述评

模压全息技术作为一种高科技已在近年来得到迅速的发展并趋于成熟,模压全息能以较低的成本和较高的速度进行大批量的工业化生产。本文对我国模压全息技术发展现况进行了述评。     

低空间频率银盐明胶全息图的浮雕特性研究及其应用

通过实验研究表明，对低空间频率的振幅型银盐全息图形表面已形成浮雕，经漂白，浮雕深度成倍加深；浮雕深度随空间频率而变化，并且可用不同曝光量进行调制。选择适当条件，可降低零级光强，提高全息图的一级衍射效率。     

乳胶厚度对卤化银反射全息图衍射特性的影响

实验研究了自制的超细颗粒卤化银乳剂SDUF－1分别在AAC显影、改进的R－10漂白处理及改进的GP－8溶解物理显影处理条件下，其乳胶厚度对反射全息图衍射特性的影响。实验结果表明，在这两种不同处理条件下衍射效率与胶厚的关系有相当大的差别，合适的乳胶厚度分别为12μm和6μm左右。     

Recent Advances on High-Speed and Holographic Two-Photon Direct Laser Writing

Two-Photon Lithography, thanks to its very high sub-diffraction resolution, has become the lithographic technique par excellence in applications requiring small feature sizes and complex 3D pattering. Despite this, the fabrication times required for extended structures remain much longer than those of other competing techniques (UV mask lithography, nanoimprinting, etc.). Its low throughput prevents its wide adoption in industrial applications. To increase it, over the years different solutions have been proposed, although their usage is difficult to generalize and may be limited depending on the specific application. A promising strategy to further increase the throughput of Two-Photon Lithography, opening a concrete window for its adoption in industry, lies in its combination with holography approaches: in this way it is possible to generate dozens of foci from a single laser beam, thus parallelizing the fabrication of periodic structures, or to engineer the intensity distribution on the writing plane in a complex way, obtaining 3D microstructures with a single exposure. Here, the fundamental concepts behind high-speed Two-Photon Lithography and its combination with holography are discussed, and the literary production of recent years that exploits such techniques is reviewed, and contextualized according to the topic covered.     

An ocular wavefront sensor based on binary phase element: design and analysis

A modal wavefront sensor for ocular aberrations exhibits two main advantages compared to a conventional Shack–Hartmann sensor. As the wavefront is detected in the Fourier plane, the method is robust against local loss of information (e.g. local opacity of ocular lens as in the case of cataract), and is not dependent on the spatial distribution of wavefront sampling. We have proposed a novel method of wavefront sensing for ocular aberrations that directly detects the strengths of Zernike aberrations. A multiplexed Fourier computer-generated hologram has been designed as the binary phase element (BPE) for the detection of second-order and higher-order ocular aberrations (HOAs). The BPE design has been validated by comparing the simulated far-field pattern with the experimental results obtained by displaying it on a spatial light modulator. Simulation results have demonstrated the simultaneous wavefront detection with an accuracy better that ～λ/30 for a measurement range of ±2.1λ with reduced cross-talk. Sensor performance is validated by performing a numerical experiment using the City data set for test waves containing second-order and HOAs and measurement errors of 0.065?µm peak-to-valley (PV) and 0.08?µm (PV) have been obtained, respectively.     

混合光环晶格的实验研究

混合光环晶格是由束腰半径相同、拓扑电荷数分 别为整数和分数的两束拉盖尔-高斯(LG,Laguerre-Gaussian)涡旋光束共轴叠加 而成。本文理论模拟产生了混合光环晶格,包括混合亮环晶格和混合暗环晶格;基于共轭对 称延拓傅里叶 计算全息生成了混合光环晶格的全息图,并利用反射式空间光调制器(SLM),光电再现了高 质量的混合光环 晶格,实验结果与理论模拟一致。研究表明,混合光环晶格可以揭示拓扑电荷数的变化对 光环晶格的光束 分布影响,对深入理解复合涡旋光束提供了实验依据。     

计算全息再现中LCD黑栅效应的研究

在基于LCD再现的计算全息中,由于TFT-LCD固有的像素结构形成一个二维黑栅矩阵,其衍射作用会引入阵列分布的多个像,即黑栅效应,影响再现像的像质.通过理论推导,具体分析了LCD黑栅效应对全息再现像的影响;提出像素分解法,分别模拟理想再现和基于LCD再现的过程,得到相应的数字再现像.并对其进行了比较和分析,给出了分析结果,证实了LCD黑栅效应对再现像的影响.     

Simple optical decryption based on a modified joint transform correlator technique

Optical information security has become one of themain contenders in various encryption and decryptiontechniques for information security applications,with u-nique advantages including a high level of security dueto its pure optical information processing…     

新型四通道计算全息图

提出了一种新的制作四通道计算全息的方法,它在双通道计算全息的基础上通过在一个抽样单元中放置两个宽度和高度均可变化的矩形,实现在u方向和v方向各记录两个物体的信息,从而可以一次性记录四个物体.该方法已经在实验中得到了印证,文中给出了相应的原理和实验结果.