紫外衍射微透镜阵列的设计与制备

为了提高紫外焦平面阵列的填充因子,可以通过微透镜阵列与紫外焦平面阵列的集成,以改善紫外焦平面阵列的探测性能。根据标量衍射理论设计了用于日盲型紫外焦平面阵列的128×128衍射微透镜阵列,其工作中心波长为350nm,单元透镜F数为F/3.56。采用组合多层镀膜与剥离的工艺方法制备了128×128衍射微透镜阵列,对具体的工艺流程和制备误差进行了分析,测量了衍射微透镜阵列的光学性能。实验结果表明:衍射微透镜阵列的衍射效率为88%,与理论值95%有偏差,制备误差主要来自对准误差和线宽误差。紫外衍射微透镜阵列具有均匀的焦斑分布,与紫外焦平面阵列单片集成能较好地改善器件的整体性能。     

凹折射微透镜阵列的离子束刻蚀制作

利用光刻热熔成形工艺及离子束刻蚀制作 12 8× 12 8元凹微透镜阵列。所制硅及石英凹微透镜的典型基本图形分别为凹球冠形、凹柱形和矩顶凹面形。分析了在光致抗蚀剂柱凹微透镜图形制作过程中的膜系匹配特性 ,与制作该种微透镜有关的光掩模版的主要结构参数 ,以及光致抗蚀剂掩模工艺参数的控制依据等。探讨了在凹微透镜器件制作基础上利用成膜工艺开展平面折射微透镜器件制作的问题。采用扫描电子显微镜 (SEM)和表面轮廓仪测试了所制石英凹微透镜阵列的表面微结构形貌。给出了所制石英凹微透镜阵列远场光学特性的测试结果。     

电寻址空间光调制器“黑栅”效应的消除方法

提出了两种消除电寻址空间光调制器由于低开口率所引起的"黑栅"效应的方法:利用衍射微透镜阵列的方法和利用纯相位型光束整形器件阵列的方法.分析了这两种方法的基本原理,给出了微透镜阵列和光束整形器件阵列的设计思想,并比较了这两种方法的异同点.采用杨一顾相位恢复算法得到了光束整形结果.理论分析及仿真计算表明:这种方法均能有效地消除电寻址空间光调制器相邻象素之间的黑带.     

微模塑法制备PMMA球面微透镜阵列

借助微透镜及其阵列的光学器件,采用软刻蚀技术中的微模型方法成功制备了聚甲基丙烯酸甲酯(PMMA)的柱体及球面微透镜阵列,并对该微透镜阵列进行了光学显微和SEM分析．通过考察制备过程中的影响因素,探讨了减少阵列缺陷和提高光学性能的适宜参数．并对该透镜阵列的光学成像性能进行了初步研究．     

基于微透镜阵列的LED光学性能

功率型发光二极管(LED)的发展迫切需要提高取光效率,基于微透镜阵列的二次光学设计是改善其取光效率的有效途径。建立了一种大功率LED的封装结构,二次光学设计采用了微透镜阵列技术,运用光线追踪法研究了这种封装结构的光学性能。分析结果表明:利用微透镜阵列技术能显著改善LED的光学性能,提高取光效率,能将LED的亮度衰减降低12%以上,得到了较好的效果。     

衍射微透镜列阵在Shack-Hartmann波前传感器中的应用

菲涅耳衍射微透镜列阵是目前广泛应用的衍射光学元件之一,它是基于衍射原理,由计算机设计,并通过微细加工技术制作成的.本文介绍了8相位台阶菲涅耳衍射微透镜列阵的制作方法,并描述了一个用16×16微透镜列阵形成的小型 Shack-Hartmann 波前传感实验系统,用该系统可对入射波前进行测量和重建.     

微透镜阵列光学相控阵扫描技术研究进展

光学相控阵光束扫描技术在激光雷达、空间光通信和光开关等领域拥有巨大的应用潜力。微透镜阵列光学相控阵可以通过微透镜阵列间μm量级的相对位移同时对多个出射光束的二维倾斜相位进行调制,从而实现大角度二维光束扫描,具有出射口径大、结构简单、体积小、微惯性、多功能等优点。首先介绍了微透镜阵列光学相控阵的扫描原理,之后对微透镜阵列光学相控阵国内外的发展现状、应用和现阶段存在的问题进行了阐述,最后对微透镜阵列光学相控阵的发展趋势进行了展望。     

平面交叉玻璃波导型微透镜阵列光学性能研究

介绍了平面交叉玻璃光波导型半球形微透镜阵列的制作方法.利用积分形式的光线方程式讨论了半球形微透镜的光学特性,得到了半球形微透镜的光线轨迹方程式和焦距表示式,理论结果与实验数据是一致的.     

基于微透镜阵列匀束的激光二极管面阵抽运耦合系统分析

为了提升高功率固体激光器中激光二极管(LD)面阵抽运场性能,采用几何光学和数理统计分析的方法,建立了基于微透镜阵列匀束的LD面阵抽运耦合系统的数学与物理模型,对微透镜阵列参数与最终耦合输出抽运场参数之间的关系进行分析,明确了微透镜单元F数、微透镜通光单元数以及微透镜阵列空间周期参数的设计原则.经实验测试,优化设计完成的LD面阵抽运耦合系统光场不均匀度为7.9%,耦合效率为90.7%.     

基于填充因子的微透镜阵列扫描光学系统性能分析

针对通过微透镜阵列通光孔径的光束在不同条件下的填充问题,利用填充因子来表征微透镜阵列系统光瞳位置处光束的填充率,并分析其对系统探测距离、点扩散函数和光学传递函数的影响。基于近轴光学模型,构建了快速计算微透镜阵列扫描光学系统填充因子的数学模型,并提出一种系统设计方法。利用该方法设计了微透镜阵列扫描光学系统,所设计系统的实验结果与理论计算结果吻合,表明该系统的性能良好。     

用液晶空间光调制器产生光阱阵列

液晶空间光调制器能够方便地用于制作各种衍射型光学元件, 但液晶空间光调制器存在分辨率有限的缺点, 本文提出了用液晶空间光调制器制作相位型光栅, 产生一维和二维光阱阵列的新方案, 用迭代傅里叶级数算法优化设计光栅的相位分布, 在不改变空间光调制器硬件参数设置的情况下, 充分利用和发掘了空间光调制器的优点, 同时又能较好地回避其所存在的缺陷. 根据现有的空间光调制器的技术参数, 模拟仿真设计光栅, 计算光强分布, 结果表明: 用大失谐、小功率激光照明, 能够产生具有很高峰值光强和光强梯度的光阱阵列, 囚禁冷原子的光学偶极势达到mK量级, 对原子的作用力远大于原子的重力.     

Light efficiency of liquid crystal spatial light modulator using,for wavefront corrector in AO

Liquid crystal spatial light modulator (LC-SLM) has a series of attractive characteristics as a wavefront corrector in adaptive optics system such as compactness, high density integration, low cost and possibility of batch production. However it also suffers from several drawbacks such as low light efficiency. We present an analysis of the light efficiency of the phase by only using LC-SLM for wavefront corrector in AO system. The factors of polarization sensitive, pixel grid structure, phase quantization and limited phase stroke are discussed in theory. Simulation results are given based on a math model of a LC-SLM. The intensity variation results from pixel structure are measured. The light efficiency of the LC-SLM is tested for generating a series of Zernike aberrations. The effect of phase wrapping method is analyzed and tested. We demonstrate that the light efficiency reduces these factors. Experiment results from the use of the phase only liquid crystal spatial light modulator confirms these conclusions.     

利用纯相位型液晶空间光调制器实现空心光束

为了提高激光系统的整体效率,需要将出射光强整形为空心分布。采用纯相位型液晶空间光调制器整形近高斯分布光强到空心分布。基于能量守恒定律和等光程原理,分析了纯相位型液晶空间光调制器光束整形系统,得出了整形系统所需的相位分布。采用衍射光学方法,数值模拟了整形效果,讨论了入射光束束腰半径和强度分布等因素对整形效果的影响。利用纯相位型液晶空间光调制器实验实现了空心光束,实验测得的转换效率大于99%。     

无衍射特殊光束的产生与三维表征

无衍射光束(如贝塞尔光束、艾里光束)因具有无衍射、自愈合的特性, 在很多领域都有广泛的应用. 本文提出使用纯相位型空间光调制器对光场的复振幅进行调控, 从而可以产生多种复杂模式的无衍射光束, 如强度可独立调控的多个零阶贝塞尔光束, 两个高阶贝塞尔光束干涉生成的花瓣状无衍射光束, 具有多个主瓣的加速光束等特殊的无衍射光束. 通过在待测焦场附近放置一个平面反射镜, 使其沿光轴快速扫描光场, 并由数字相机同步拍摄反射回来的一系列二维光场强度分布信息, 可实现对无衍射光束三维光场强度分布的快速测量和表征. 本实验方法和技术可以快速产生各种复杂的特殊光场并获得其精确的三维可视化重建效果, 在光学显微、光学俘获、光学微加工等领域有潜在的应用价值.     

可操控二种冷原子或冷分子样品的光学双阱新方案及其实验研究

提出了一种构建可囚禁与操控二种冷原子或冷分子样品的光学双阱的新方案,该方案采用常用的液晶空间光调制器作为分光器件,分光调制函数类似二元相位光栅;对提出的方案进行了模拟实验研究,并研究了从光学双阱到单阱的双向演化过程,该光学双阱的模拟实验结果表明与理论方案相符,双阱的操控性好,有利于二种不同的冷原子或冷分子样品的装载与操控等相关实验研究. 关键词： 原子光学 原子分子囚禁 液晶空间光相位调制器 光学双阱     

基于空间光调制器的多层图像的构建与可视化研究

 为解决实时直观地观察多层再现图像的问题,提出利用发光材料实现其可视化.针对由沿光轴方向的二维图层组成的空间图像,利用高效、快速的三维Gerchberg-Saxton算法,得到位相型计算全息图,并通过计算机进行了数字模拟再现.阐述了三维Gerchberg-Saxton算法的流程,并搭建了基于液晶空间光调制器的位相全息图光学再现与可视化光路.利用液晶空间光调制器的灰度-位相曲线把计算全息图转换为灰度图,加载在液晶空间光调制器上,再现出高质量的三维光场,同时利用量子点材料的荧光特性实现了图像的可视化.实验结果表明,光学再现与计算机模拟结果较吻合.该技术在医学、军事、三维显示、微加工以及显微技术等领域有重要应用价值.     

Two-Dimensional Multi-Lens Array with Circular Aperture Spherical Lens for Flat-Top Irradiation of Inertial Confinement Fusion Target

A two-dimensional multi-lens array 350 mm in diameter with spherical element lenses has been tested to improve the irradiation uniformity of a high power glass laser for inertial confinement fusion (ICF). A circular shape for the element lens aperture is chosen to eliminate azimuthally asymmetric intensity distribution. An approximate flat-top intensity distribution is obtained with a lens array of 37 lenses. Beam patterns of a coherent laser and partially coherent light (PCL) with the random phase plate (RPP) and the multi-lens array (MLA) are measured in a GEKKO XII glass laser system. Spherical mode structure of the irradiation nonuniformity of 5.6% with MLA is estimated with cos3 θ distribution of absorption coefficient in the target plasma.     

Lenticular arrays based on liquid crystals

Lenticular array products have experienced a growing interest in the last decade due to the very wide range of applications they can cover. Indeed, this kind of lenses can create different effects on a viewing image such as 3D, flips, zoom, etc. In this sense, lenticular based on liquid crystals (LC) technology is being developed with the aim of tuning the lens profiles simply by controlling the birefringence electrically. In this work, a LC lenticular lens array has been proposed to mimic a GRIN lenticular lens array but adding the capability of tuning their lens profiles. Comb control electrodes have been designed as pattern masks for the ITO on the upper substrate. Suitable high resistivity layers have been chosen to be deposited on the control electrode generating an electric field gradient between teeth of the same electrode. Test measurements have allowed us to demonstrate that values of phase retardations and focal lengths, for an optimal driving waveform, are fairly in agreement. In addition, results of focusing power of tuneable lenses were compared to those of conventional lenses. The behaviour of both kinds of lenses has revealed to be mutually similar for focusing collimated light and for refracting images.     

Programmable aperture microscopy: A computational method for multi-modal phase contrast and light field imaging

We demonstrate a simple and cost-effective programmable aperture microscope to realize multi-modal computational imaging by integrating a programmable liquid crystal display (LCD) into a conventional wide-field microscope. The LCD selectively modulates the light distribution at the rear aperture of the microscope objective, allowing numerous imaging modalities, such as bright field, dark field, differential phase contrast, quantitative phase imaging, multi-perspective imaging, and full resolution light field imaging to be achieved and switched rapidly in the same setup, without requiring specialized hardwares and any moving parts. We experimentally demonstrate the success of our method by imaging unstained cheek cells, profiling microlens array, and changing perspective views of thick biological specimens. The post-exposure refocusing of a butterfly mouthpart and RFP-labeled dicot stem cross-section is also presented to demonstrate the full resolution light field imaging capability of our system for both translucent and fluorescent specimens.     

Pixel size and pitch measurements of liquid crystal spatial light modulator by optical diffraction

We present a simple technique for the determination of pixel size and pitch of liquid crystal (LC) based spatial light modulator (SLM). The proposed method is based on optical diffraction from pixelated LC panel that has been modeled as a two-dimensional array of rectangular apertures. A novel yet simple, two-plane measurement technique is implemented to circumvent the difficulty in absolute distance measurement. Experimental results are presented for electrically addressed twisted nematic LC-SLM removed from the display projector.