Optical Pickup with a Spherical Aberration Compensator Using a Crossed-Stripe Liquid Crystal Device

To increase recording density in an optical disk system, a two-lens system which enlarge its numerical aperture (NA) has been developed. When NA becomes larger, however, the spherical aberration due to disk thickness error increases. We propose an optical pickup with a spherical aberration compensator using nematic liquid crystal (LC). Our LC device is composed of two LC cells each of which has X and Y stripe electrodes, respectively. We discussed how the spherical aberration due to the disk thickness error can be compensated by combination of two crossed cylindrical phase distributions induced by the LC cells, and confirmed the compensation effect in a design example by simulation. We have also fabricated the crossed stripe LC device actually, and have obtained the experimental result which shows that amount sufficient to compensate the aberration is achieved.     

Characterization of aplanatic hologram lenses for optical disk pick-ups

Imaging characteristics for holographic objective lenses application to optical disk pick-ups was analyzed by a comparison between flat and spherical aplanatic hologram lenses with the aid of the third order aberration theory and ray tracing method. The aplanatic hologram lens image field was 0.5 deg for NA=0.5 with focal length f=5 mm under the Marechal criterion. The results indicates that the aplanatic hologram lenses are feasible for optical disk applications.     

Diffractive-Refractive Achromatic Lens for Optical Disk System by Glass Molding

An erasable optical disk system requires an objective lens having minimum chromatic aberration. We estimated the chromatic aberration of a conventional refractive singlet. At shorter wavelengths, the focus shift of an objective lens exceeds its depth of focus. A diffractive-refractive hybrid lens can compensate chromatic aberration perfectly. Diffraction efficiency, however, decreases with the degree of compensation. We simulated the relationship between chromatic aberration and diffraction efficiency. Fabrication of designed lenses by glass molding was achieved, and the results showed excellent agreement with the simulation.     

折反射式零位补偿检验(续)

为了研究双透镜和球面镜之间不同球差分配对折反射式补偿器补偿效果的影响,以三级像差理论为基础,针对两个不同相对口径的凹抛物面镜,采用不同内部球差分配,分别设计了一组折反射式补偿器,将结果绘制成曲线.从曲线可看出,当球面镜球差分配系数从0逐渐增大到0.5时,对应折反射式补偿器补偿能力先增强,达到极值后下降.球面镜球差分配系数为零时,球面镜不承担球差,球面镜变成半径无穷大的平面镜,折反射式补偿器即变为Offner补偿器.研究表明,折反射式补偿器补偿能力强,但不同内部球差分配对补偿效果影响较大,合理选择球面镜球差分配系数对折反射式补偿器设计是有利的.     

Cc,Cs, and parasitic correction in quadrupole probe-forming lenses

Approximate expressions are derived for the second and third order aberrations of a quadrupole doublet, allowing for aberrations intrinsic to fields of perfect symmetry, for parasitic aberrations of imperfect symmetry, and for compensating multipole lenses. Five third-order coefficients are found, and expressed in terms of four octopole strengths and the first-order parameters of the doublet as determined by its dimensions. For compensation of third-order aberrations of achromatic quadrupole/octopole lenses, either skew octopole lenses are required externally, or lenses with more than 8 poles are required coincident with the quadrupoles. If an octopole lens is added between the quadrupoles of the achromatic doublet, the spherical aberration of a condenser lens may be compensated. Such a Cs and Cc compensated quadrupole doublet is suitable for use as a probe-forming lens in focused ion beam systems and ion microscopes.     

二次曲面前房型有晶体眼人工晶体的球差矫正特性分析

为探究二次曲面前房型有晶体眼人工晶体的球差矫正特性,进行了球面和二次曲面有晶体眼人工晶体的设计,并利用像差理论对二者的球差矫正特性进行了研究.基于R.Navarro等人提出的模型眼得到屈光不正眼模型,利用ZEMAX光学软件分别设计了可矫正屈光不正人眼的球面与二次曲面前房型有晶体眼人工晶体.通过对光学传递函数和Zernike球差系数的比较,以及对Seidel球差分布系数的计算分析发现:在保证屈光不正矫正至正常水平的前提下,较之传统球面人工晶体,二次曲面的引入仅对远视眼的球差有矫正作用,并使光学传递函数显著改善|而对近视眼而言,二次曲面人工晶体的球差矫正效果与球面人工晶体相当.这一结论对前房型有晶体眼人工晶体的设计和应用具有重要的理论指导意义.     

Circular modes selection in Yb:YAG laser using an intracavity lens with spherical aberration

The possibility of use of ordinary short-focus lenses with strong spherical aberration for mode selection in a laser resonator is demonstrated. Plano-convex spherical lenses with foci from 2.5 to 10.0 cm placed inside the resonator of the CW laser diode pumped Yb:YAG laser were used to select circular modes of Laguerre-Gauss and Bessel-Gauss type, or to get ring-like, multi-mode off-axis oscillations with variable inner and outer diameters of rings. At the constant pump power mode selection was obtained by shifting an intracavity lens along the resonator axis relative to the Yb:YAG ceramics active element of 1.1 mm thickness. Peaked and hollow multi-ring beams with output power up to 30 mW were produced. Near diffraction free (ndf) propagation of the central part (minimum or maximum) of these beams was observed along distances over 10 m from the resonator output coupler. The mechanisms of mode selection due to spherical aberration in the resonator and ndf propagation of output beams are considered. The possibility of producing radially polarized beams from the laser with an intracavity lens and possible applications of the devised laser scheme are discussed.     

三维光存储中折射率失配引起的球差补偿

为实现三维光存储中折射率失配引起的球差补偿,建立了光学存储系统模型,获得了折射率失配引起的波前偏差函数与存储深度的表达式.采用泽尔尼克循环多项式对波前偏差函数进行补偿展开.在双光子荧光和单光子共焦荧光读出方式下,均可获得读出荧光强度与存储深度的关系:在折射率失配引起的球差未得到补偿矫正的情况下,存储深度在200 μm左右读出荧光强度基本上下降为零;当折射率失配引起的初级球差被补偿矫正后,读出荧光强度随存储深度的下降得到较好改善;当折射率失配引起的二级球差被补偿矫正后,存储深度在1 mm内存储点强度随深度基本上没有明显地变化.并且对像差补偿方法进行了具体地分析.     

On the chromatic aberration of magnetic lenses with a field distribution in the form of an inverse power low (B(z) ∝ z)

The chromatic aberration of magnetic lenses with the field distribution in the forms of inverse law have been studied by analytical and digital methods. These aberrations can be expressed in terms of Bessel function of fraction order. Analytical expressions for chromatic aberration coefficients of the spherical field model, which is useful for the study of single-pole magnetic lenses, are given.     

渐进多焦点镜片波前像差的扩束测量方法

利用波前传感器测量自由曲面镜片时,由于自由曲面镜片的直径通常大于波前传感器的接收孔径,主要采用子孔径拼接技术测量镜片的波前像差。针对子孔径拼接技术测量中存在着操作繁琐、数据处理量大等问题,提出渐进多焦点镜片波前像差的扩束测量方法,得到渐进多焦点镜片中央直径为22 mm圆形区域内的波前像差。为了验证试验的可靠性,将测量得到的波前像差泽尼克表述中的离焦项转换为球镜度,与条纹偏折法测量得到镜片的球镜度进行对比实验,实验结果证明了渐进多焦点镜片波前像差的扩束测量方法可以用于渐进多焦点镜片波前像差的检测。     

高斯光束经过负球差透镜的聚焦

本文讨论高斯光束经过负球差透镜的聚焦，得到了聚焦光场轴上点的光强分布的表示式，并对其进行数值计算。数值计算结果表明，在负球差的情况下，得到光强的最大点位置（最佳聚焦点）相对于无球差情况，往透镜方向移动，并且，最佳聚焦点的光强较无球差时大，当Ｎｗ＝１，Ｎａ＝５，ｋＳ１＝－０．２时，得到的最佳聚焦点的光强是无球差时的１．３４倍。本文还讨论了透镜的菲涅尔数对聚焦光场分布的影响。结果表明，当透镜的菲涅尔数小于１时，球差对高斯光束的聚焦的影响可以忽略。     

车载摄影摄像装置图像偏移与动态几何像差的分析

对利用车载摄影摄像装置进行路面检测的检测车,由于检测车行驶时车身存在振动,其检测精度由图像偏移量与动态几何像差决定。为提高检测精度,必须确定任一时刻的图像偏移量与动态几何像差并对其进行补偿。利用刚体绕定点有限转动的欧拉定理推导了图像偏移函数与动态几何像差函数,计算了为使图像清晰而需在任一时刻对图像的偏移进行补偿的补偿量和对焦距、像面位置、透镜位置进行调整的调整量。研究为图像偏移和动态几何像差补偿的实现奠定了理论基础。     

Vision improvement by correcting higher-order aberrations with customized soft contact lenses in keratoconic eyes

Higher-order aberration correction in abnormal eyes can result in significant vision improvement, especially in eyes with abnormal corneas. Customized optics such as phase plates and customized contact lenses are one of the most practical, nonsurgical ways to correct these ocular higher-order aberrations. We demonstrate the feasibility of correcting higher-order aberrations and improving visual performance with customized soft contact lenses in keratoconic eyes while compensating for the static decentration and rotation of the lens. A reduction of higher-order aberrations by a factor of 3 on average was obtained in these eyes. The higher-order aberration correction resulted in an average improvement of 2.1 lines in visual acuity over the conventional correction of defocus and astigmatism alone.     

用等光程法设计非球面

本文介绍如何用等光程法设计一个非球面,用来准确校正聚光系统的球差.不但给出公式推导,而且给出两个设计实例.     

模拟合成孔径雷达数据片波差的测量和胶片、波差的容限

本文介绍一种用马赫-陈德干涉系统测量模拟合成孔径雷达数据片波差的方法.该法能把两种原因产生的波差区分开来,即把通过胶片变形的波面与平面参考波面比较,求出胶片厚度不平产生的波差;把合成孔径雷达数据片的一级衍射波面与两个半径不等的参考球面波比较,分别求出由模拟装置产生的方位维和斜距维波差.本文给出一些实验结果和分析.这种方法还可以用于测量真实合成孔径雷达数据片的波差.由胶片厚度变化产生的波差可以用液体门补偿.但是,在实际中使用液体门是很繁复的,有时也没有必要.因此,我们认瑞利准则出发导出合成孔径雷达数据片胶片厚度变化产生的波差的容限,以此作为判断是否要用液体门的依据.     

Verbesserung der Auflösung im Elekronenmikroskop durch Bildebenen-Holographie

Enhancement of resolution in electron microscopy can be achieved by use of electron image holography. In order to compensate for the aberrations of the electron lenses the reconstruction is performed with laser light in an optical system with suitably adapted aberrations. The partial coherence in connection with the aberrations of the electron lenses limits the possible resolution. The limits of resolution dependent on defocusing and spherical aberration are calculated.     

抛物面型X射线组合折射透镜聚焦性能的理论与实验研究

结合衍射理论和矩阵光学方法得出抛物面型X射线组合折射透镜的光学性能指标(包括其焦距的严格表达式、薄透镜近似的判定准则、透过率和有效孔径,以及极限聚焦光斑尺寸等).采用X射线深度光刻技术实际制作了PMMA材料抛物面型X射线组合折射透镜并给出了工艺测试结果.最后在北京同步辐射装置(BSRF)上,实际构建了基于3种不同结构参数的PMMA材料抛物面型X射线组合折射透镜的微束聚焦实验系统.并实际测试了其聚焦性能,均获得了良好的聚焦效果,给出实测结果并对实测结果进行了分析和讨论.     

Subjective evaluation of intraocular lenses by visual acuity measurement using adaptive optics

We present a new method for subjectively evaluating intraocular lenses (IOLs) without implantation surgery. To illustrate the method, three types of single-piece IOL (equispherical monofocal, rotational symmetric aspheric monofocal, and diffractive bifocal) were assembled into a model eye and evaluated using an ocular adaptive optics system by a single subject. To separate the spherical aberration of the crystalline lens, the subject's corneal topography and wavefront aberrations were measured and modeled. Three levels of Zernike spherical aberration were generated and superposed on the IOLs and the subject's eye. The corrected distance visual acuity was measured by psychophysical visual procedure.     

左手性介质透镜系统的赛德尔像差特性研究

根据初级像差理论，系统研究了由左手性介质构造的透镜系统的赛德尔像差特性.分析了左手性介质单折射曲面的赛德尔像差特性，发现其消初级球差的曲面类型比普通介质更为灵活且可用于实成像系统.依据薄透镜赛德尔和数公式，分析和设计了三种只有左手性介质才具备的可消部分赛德尔像差的薄透镜结构参数，提出了几种能同时消除全部五种赛德尔像差的由左手性介质构造的透镜组合系统.研究表明左手性介质相对于普通介质在消像差方面存在较大优势，在光学设计时可以采用更少的折射表面个数或更简单的表面形状即可到达同等的成像性能.     

磁圆形透镜和磁六极透镜的复合系统的象差

近来磁六极透镜作为球差校正器引起了人们的注意。本文研究了磁圆形透镜和磁六极透镜的场分布叠加形成的复合系统的象差。我们在复数域中定义了内积,采用了复数的表象和微分算符,全面讨论了这种复合系统的高斯光学性质及二、三、四级象差,得出了各级象差所有的象差系数的公式。 关键词：