可编程菲涅耳相位透镜应用于多平面全息投影

研究了基于菲涅耳相位透镜实现多平面全息投影的方法,采用硅基液晶相位调制器建立了多平面全息投影系统.首先,利用可编程菲涅耳相位透镜代替傅里叶透镜,将计算机生成的相位全息图与菲涅耳透镜的相位结合;其次,基于时分复用和空分复用原理提出了加载菲涅耳相位透镜与相位全息图到相位空间光调制器上的两种方法;最后,讨论了在多平面全息投影中每个单一平面实现旋转物体动态360°视角显示的方法.实验结果表明:在距离硅基液晶分别为500、800、1 100和1 400mm处的四个重构平面可以获得全息投影图像;通过动态地改变菲涅耳相位透镜的焦距,可以实现多平面全息投影.     

菲涅耳微透镜列阵衍射效率的测试与分析

归纳了目前二元位相型菲涅耳微透镜列阵衍射效率测试中所用各种衍射效率的不同定义，提出规范定义的建议。并设计了测量衍射效率的系统，方法简单易行，适于测试具有微小单元尺寸的菲涅耳微透镜列阵的衍射效率。     

线宽误差对菲涅耳透镜衍射效率的影响

基于标量衍射理论,首先得出存在线宽误差情况下4阶菲涅耳透镜衍射效率的解析式;并以 4阶、8阶和16阶菲涅耳透镜为例,进行计算机模拟计算并系统分析线宽误差对菲涅耳透镜衍射效率的影响。通过实验测量16阶菲涅耳透镜的线宽误差,分析其对16阶菲涅耳透镜衍射效率的影响。模拟计算结果对多阶菲涅耳透镜的制作提供重要的理论指导。     

菲涅耳微透镜行列阵衍射效率的测试与分析

归纲了目前二元位相型菲涅耳微透镜列阵衍射效率测试中所用各种衍射效率的不同定义，提出规范定义的建议。并设计了测量衍射效率的系统，方法简单易行，适于测试具有微小单元尺寸的菲涅耳微透镜列阵的衍射效率。     

随机位相菲涅耳透镜阵列激光束匀化

为降低干涉带来的影响,将一种随机位相分布引入菲涅耳透镜阵列,对阵列中每一个菲涅耳透镜施加0或π的二值化位相变化,打乱阵列位相的周期性排布,减少微透镜后多光束在匀化面干涉带来的影响.通过数值计算对激光束的匀化过程进行了模拟,设计的菲涅耳透镜口径为0.5 mm,焦距为6mm,阵列数目为20×20,光斑整体均匀度达到90%,光束能量利用率达到96%.利用设计和制备的16台阶随机位相型菲涅耳透镜阵列对1 064nm波长的激光光束进行匀化,均匀度为83%,光束能量利用率为89%.研究结果表明,通过引入随机位相可有效减少干涉带来的影响,提高微透镜阵列对单模高斯光束的匀束效果.     

基于纯位相液晶空间光调制器的可变焦透镜的实现

提出一种基于纯位相液晶空间光调制器(LC-SLM)实现变焦透镜的方法。根据液晶空间光调制器的位相调制原理,以相息图控制LC-SLM来调制入射光波,并衍射产生透镜波面,改变相息图的衍射距离,可实现变焦位相菲涅耳透镜的功能。分析衍射孔径、衍射距离、相息图位相阶数等参数对变焦位相菲涅耳透镜的影响,并以点光源相息图为例对该方法的可行性进行了实验验证。实验结果表明:通过改变计算衍射距离,提出的方法可得到焦距不同的透镜,且易于控制,为三维扫描显示的实现提供了可行性依据。     

基于紫外纳米压印的菲涅耳透镜制作

针对传统聚光系统中菲涅耳透镜成本较高并且光强分布不均匀的弊端,提出了利用紫外纳米压印技术制作菲涅耳透镜的方法.利用几何光学的光线追迹理论,设计了菲涅耳透镜模具.采用自行研制的紫外纳米压印系统对模具进行压印,紫外曝光后制得薄膜菲涅耳透镜.在太阳光下进行了测试,测试结果表明,低成本、高聚光倍数和光强分布均匀的菲涅耳透镜是可以实现的.     

基于紫外纳米压印的菲涅耳透镜制作

针对传统聚光系统中菲涅耳透镜成本较高并且光强分布不均匀的弊端,提出了利用紫外纳米压印技术制作菲涅耳透镜的方法.利用几何光学的光线追迹理论,设计了菲涅耳透镜模具.采用自行研制的紫外纳米压印系统对模具进行压印,紫外曝光后制得薄膜菲涅耳透镜.在太阳光下进行了测试,测试结果表明,低成本、高聚光倍数和光强分布均匀的菲涅耳透镜是可以实现的.     

表面反射对菲涅耳透镜的影响

使用薄膜沉积法制作16阶菲涅耳透镜,用它代替常规的光学透镜可实现系统的轻量化,小型化,并增加系统设计的自由度,在标量衍射理论的基础上,应用菲涅耳公式和傅里叶变换分析SiO2薄膜和基底的表面反射对菲涅耳透镜－1级衍射效率的影响,结果表明表面反射对菲涅耳透镜的成像质量影响较大,可以通过蒸镀增透膜来减小这种影响。     

菲涅耳透镜的制作及性能分析(对准误差的影响)

我们使用薄膜沉积法制作16阶菲涅耳透镜,其衍射效率接近87%.用它代替常规的光学透镜可实现系统的轻量化、小型化、增加系统设计的自由度.在标量衍射理论的基础上,应用菲涅耳公式和傅里叶变换分析SiO₂薄膜和基底的表面反射、对准误差以及入射角对16阶菲涅耳透镜衍射效率的影响.     

全息透镜的焦距测量

本文首先给出了全息透镜像散成像的焦距公式,介绍了用全息光栅法测量全息透镜焦距的原理,对两块自制的全息透镜在原光路再现情况下测量了其焦距,并用另一种参数测量方法对测量结果进行了验证,两者基本相符。通过分别测量全息透镜两个焦距,从而可得出其像散大小。最后指出了使用这种方法应注意的问题。     

信息光学实验器件与实验技巧

对半导体激光器用于全息记录的特性进行了实验研究 ,指出了半导体激光器的优点及在光学全息领域应用的巨大潜力 ;分析了三种傅立叶变换透镜的共性和差别 ,提出了会聚光中傅立叶变换透镜的优点和光学设计的基本规律 ,实验证明了所设计的实例有良好的结果。     

体全息存储系统中的傅里叶变换透镜设计

提出和设计了一种应用于体全息存储系统的傅里叶变换透镜,是为了适应体全息存储系统对傅里叶变换透镜的特殊要求而设计的。设计中使用了光学自动设计软件ZEMAX。综合各方面考虑,采用双平凸结构,具有以下特点:焦距短,系统结构紧凑;焦距易于改变,以方便实现不同焦距比;工作视场大,能提高体全息存储系统的存储密度;结构简单,容易加工装调,造价低。透镜组用于像素数为1k×1k的空间光调制器(SLM)与CCD匹配对准。     

Holographic Femtosecond Laser Processing with Multiplexed Phase Fresnel Lenses Displayed on a Liquid Crystal Spatial Light Modulator

Parallel femtosecond laser processing with a computer-generated hologram displayed on a spatial light modulator (SLM) is demonstrated. Use of the SLM enables performance of an arbitrary and variable patterning in laser processing. The hologram uses multiplexed phase Fresnel lenses (MPFLs) with features of independent tunability, three-dimensional (3D) parallelism of the diffraction peaks, optimization of the hologram with low computational costs, and low contribution of zero-order light to the processing. To make uniform the reconstructed diffraction peaks, an MPFL is optimized by changing the center phase and size of each phase Fresnel lens while taking account of the intensity distribution of the irradiated laser pulse and the spatial frequency response of an SLM. Using the holographic technique, two-dimensional parallel processing with a single-pulse irradiation of glass is demonstrated and the processing performance is analyzed.     

Design and fabrication of fluid controlled dynamic optical lens system

A novel small fluid controlled optical lens system that is capable of displaying dynamic variation of its focal length and field-of-view (FOV) is designed and fabricated. In this active lens system, appropriate volume of the optical fluid can be pumped into or out of the lens chamber to provide double-convex (DCX) or double-concave (DCV) lens effect. Simple optical imaging experiments were performed using different sets of glass lenses with fixed focal lengths to determine the optimum lens configuration required for designing a dynamic optical lens system. The experimental results obtained from the glass lenses demonstrate that a combination of a single DCX lens with three DCV lenses provides a wider FOV. The flexible membranes for fluid controlled lenses were fabricated using polydimethylsiloxane polymer material, which has good optical transparency and elasticity. A simple fluid injection system is used to vary the radius of curvature of the lenses, and thereby to change the focal length. A dynamic optical lens system with a combination of one DCX and multiple variable focal length DCV lenses as designed here can image an object with a wide range of focal length and FOV. With this fluid controlled optical system, the FOV and focal length could be continuously varied and a maximum FOV of 118.3° could be achieved. The smallest f-number (f_/#) for this fluid controlled single lens system was found to be 1.3, which corresponds to the numerical aperture value of 0.35.     

Light-induced lens analysis in photorefractive crystals employing phase-shifting real-time holographic interferometry

The purpose of this work is to study the potentialities of phase-shifting real-time holographic interferometry for the analysis of light-induced lens in photorefractive and nonlinear optical materials. We show that this technique can be used for quantitative evaluation of the phase distribution of a wavefront changed by a light-induced lens and, consequently, the refractive index changes in these materials. The basic principle of this technique combines real-time holographic interferometry with phase-shifting technique for interferogram analysis. This method is demonstrated with in situ visualization, monitoring and analysis in real-time and uses a Bi₁₂SiO₂₀ crystal as the holographic medium and a Bi₁₂TiO₂₀ as the test sample.     

液体透镜在变焦系统中的应用

利用液体透镜进行变焦系统设计可以大幅降低系统的复杂程度,本文介绍和讨论了该项技术的研究和应用现状。首先,基于液体透镜的分类即渐变折射率透镜和变曲率透镜介绍了几种主要液体透镜的原理和特点,给出了具有代表性的ARCTIC透镜系列和Optotune透镜系列的设计参数和优点。然后,对液体透镜技术在变焦系统中的应用进行了分析,描述了其在变焦眼镜、手机相机、内窥镜和显微镜等诸多领域中应用的现状和优势。最后,利用液体透镜设计了一种长焦距变焦系统,该系统可实现2.5倍的可见光变焦。     

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。     

Improvement of Laser-Beam Irradiation-Intensity Distribution Using Multi Lens Array and Edge-Shaped Plates

A new concept for improving the laser intensity distribution on an inertial confinement fusion target using a phase-controlled multi lens array has been proposed. Circular and hexagonal element lens apertures have been examined, and the circular aperture which eliminated azimuthally asymmetric intensity distribution was chosen. The diffraction fringe of the elementary lens was mitigated in a one-dimensional lens array using edge-shaped plates of a super-Gaussian phase profile. Uniform beam profiles were obtained using a one-dimensional array with 7 spherical lenses and a two-dimensional array with 37 lenses. An approximately flat-top intensity distribution was realized with the lens array with 37 lenses.     

曲面和平面菲涅尔透镜的像差比较

通过一个大尺寸菲涅尔透镜的设计,比较了曲面菲涅尔透镜和平面菲涅尔透镜在光学像差方面的差异。从应用角度看,菲涅尔透镜设计属于准直系统,一般采用平面结构,但由于其成像要求的特殊性,通过运用P-W方法进行分析和比较,结果表明：曲面的设计较之于平面更具优势,并在ZEMAX中分别对2种菲涅尔透镜进行建模,验证了结果的正确性。但这不表明曲面菲涅尔透镜在像差方面一定比平面菲涅尔透镜更具优势,它还与实际应用场合有关,为此,提出了不同的结构参数设计。