Acousto-optic processing of images in visible and ultraviolet light

The paper concerns processing of optical images by means of tunable acousto-optic filters. Experimental and theoretical research showed that longitudinal chromatic aberrations cause a suffcient decay of the spatial resolution in the devices. It is shown that a proper choice of an optical cheme of an imager reduces the longitudinal aberrations all over the tuning range of the filters.     

Suppression of primary chromatic aberration by genetic algorithm in an advanced telephoto lens

This paper proposes a new method for finding a suitable glass combination set for an advanced telephoto lens via a genetic algorithm (GA). Normally, glass properties, inclusive of index and Abbe number, play a significant role in the elimination of primary chromatic aberration. So many optical glasses (over 300 different refractive types) have been developed hitherto that it is difficult to choose a state-of-the-art glass combination quickly. According to the newly developed GA operations in this paper, however, several suitable glass combinations can be found quickly through a unique sequence of function selection, crossover and mutation. An advanced telephoto lens design is employed in this research, which has the characteristic of being more sensitive to axial aberrations than lateral chromatic aberrations. The GA operations are described in the macro of the optical software program, CODE V. The simulation results in this research show that the primary chromatic aberration is efficiently eliminated after the application of GA. The main goal of this research is that during optimization, error function could be minimized only if primary aberrations are well under control in our first step; in a telephoto lens, the secondary spectrum of longitudinal chromatic aberration and lateral chromatic aberration caused by distortion play a role in chromatic aberration control as well; however, optimization with a combination of both primary chromatic aberration and secondary chromatic aberration will complicate the process with a lot of working variables. The GA method introduced in this paper might efficiently eliminate the primary chromatic aberration first by finding the best glass combination and its trend and then simplifying the following optimization process for all optical systems.     

Hyperchromats with linear dependence of longitudinal chromatic aberration on wavelength

Optical lens systems that are characterized by a chromatic aberration of a predefined form are called hyperchromats. Our work describes a theory of hyperchromats with a linear dependence of longitudinal chromatic aberration on wavelength. The equations are derived for calculation of basic design parameters of these optical systems and some examples of hyperchromatic optical systems are shown. Mentioned optical systems can be used especially in 3D imaging systems and confocal microscopy.     

折/衍混合单透镜在目镜中的应用研究

以传统凯涅尔目镜为基础，采用ZEMAX软件，设计了衍射面位于目镜系统中不同位置时的折／衍混合目镜系统，所有系统均仅采用最普遍的K9玻璃，设计结果与传统凯涅尔目镜的光学性能进行了分析和比较。结果表明折／衍混合目镜系统在校正目镜的像差，例如像散，垂轴色差、垂轴像差，轴向像差和轴向色差等方面优于传统的凯涅尔目镜，选择合适的衍射面位置，可以同时获得符合要求的畸变，衍射面的引入，极大地减小了系统的重量和尺寸。     

The study of correction for chromatic aberrations of human eye with diffractive–refractive hybrid elements

A chromatic corrector with two refractive–diffractive hybrid elements is designed over a reasonable wide field-of-view of 7° to correct the chromatic aberrations of human eye. We investigate the performance of the corrector using several optical criteria in a comparison with the chromatic corrector with single refractive–diffractive element. Both the correctors can correct the longitudinal chromatic aberration (LCA) fairly. It is demonstrated that the chromatic corrector with single element introduces serious eccentric transverse chromatic aberration (TCA), which deteriorates the image quality at the edge field-of-view. On using the chromatic corrector with two refractive–diffractive elements, not only the LCA but also the TCA can be corrected very well. The designed chromatic corrector can be used to improve the retinal image quality and has potential application in the design of visual instruments.     

Optimization of 350× optical zoom lens with diffractive optical element

Through researching and validating, a set of optical designs using a diffractive optical element (DOE) and optimization process has been derived in this paper. We put forward a set of theories to solve the numerous quality issues in imaging and applied it to an optical design. For an optical design to be successful, it must comply with the standards of the optical system. Optical designers must also take into consideration imaging quality, wherein the most influential aspects are chromatic aberration and monochromatic aberration. We complied with systemic standards such as effective focal length and total system length. Diffractive Optical Element, based on the theory of wave phase difference, takes advantage of negative Abbe number, which might significantly eliminate chromatic aberrations of optics. Following the advanced technology applied to micro lens and etching process, precisely made micro DOE element now is possible to be manufactured in a large number. A 350× zoom lens with DOE is demonstrated in the proposal. The results show that regardless of whether chromatic aberration is axial or longitudinal, issues concerning the optical lens's chromatic aberration could be significantly reduced.     

自聚焦透镜列阵的色差测量

本文分析了色差的产生和表示，计算和测量了锂玻璃自聚焦透镜成像系统中的轴向色差与横向色差，讨论了色差对自聚焦透镜列阵成像的影响。     

Etude du chromatisme d'un systeme optique par photographie “speckle”

Speckle photography experiments have been used for studying optical systems and more recently we have used image speckle photography to measure displacements and deformations of a partial diffuser. The same method is now used for studying chromatic aberrations of a lens system. Experimental results are given for three optical lenses.     

紫外-可见宽光谱显微成像光学系统的设计

 介绍一个紫外-可见宽光谱显微物镜的设计过程。通过改进的PW法求解初始结构参数,确定采用两个分离的正负透镜组组成透射式光学系统,根据光学材料的色散特性,选取正透镜材料为CaF2,负透镜材料为熔石英,通过建立复消色差方程组来分配双分离透镜的光焦度,合理地对两组透镜的偏角进行分配。运用CODE-V光学设计软件对系统进行优化,使系统的位置色差和二级光谱同时得到校正,实现了复消色差。仿真结果表明：系统在整个视场范围内,点列图弥散圆RMS半径值小于5  ,最大视场处的像散为0.058,畸变为0.04 %。     

基于胶合棱镜的AOTF成像光谱仪横向色差校正

设计声光可调谐滤波器(AOTF)成像光谱仪时,ZEMAX等软件缺乏AOTF光学表面,导致光学设计困难,本文根据波矢量匹配原理,在ZEMAX中建立了基于声光衍射效应的AOTF自定义表面模型,实验表明该模型能够实现AOTF的衍射光精确追迹。在此基础上,针对传统方法校正AOTF横向色差时残差较大的问题,提出了基于胶合棱镜的高精度横向色差校正方法,结合AOTF自定义表面,完成了胶合棱镜的玻璃组合和顶角的自动优化。结果表明,文章提出的自定义表面和胶合棱镜色差校正相结合的方法大大方便了AOTF成像光谱仪的设计,能够将横向色差控制到0.000 3°,比以往方法提高了一个量级,有效抑制了光谱图像的漂移。     

同轴柱面光学系统的象差

本文首先由柱面系统中描写光线所须的参数和对称性,确定了同轴柱面系统的独立象差数是八个,而对无限远物体而言则只有六个。而后由矢量代数方法证明空间光线在柱面系统中的折射光路与发生折射率改变后的子午截面内光路全同,由此得出柱面系统有别于球面系统的二种象差与色差相当。从而导出了校正柱面象差的条件并对柱面望远镜象差作了估值。结果表明,校正柱象差一般而言是很困难的,另一方面虽不加以校正影响也不算严重。最后讨论了柱面望远镜的高斯光学,结果表明,望远镜使一方向余弦按定比例缩小,而另一方向余弦不变时,它所成出的直线的象是弯曲的。     

激光靶心冲击波观测镜折反式光学系统设计

设计了一种激光靶心冲击波观测镜的光学系统.用反射式光学系统代替折射式光学系统,解决了普通玻璃在200 nm端透过率较低的问题.反射镜不引入色差,有利于系统在200~800 nm谱段消色差.为消系统轴外像差,反射系统选型为对称式.反射镜全部采用球面镜,为消反射镜以及平板玻璃窗带入的球差,引入校正镜(材料JGS1),在满足要求的条件下,控制折射镜的厚度,使系统色差满足瑞利判据的色差允差,得到了良好的成像质量.     

Study of aberration correction in two types of electrostatic lenses

A detailed comparative study is carried out of chromatic and spherical aberration in a crossed lens and in a lens formed by four cylindrical electrodes, the two inner ones of which are cut into four symmetrical longitudinal sections. The study was performed by numerical modeling. The possibility of simultaneous correction of both types of aberration in a linear image is demonstrated. A comparison is made with an equivalent axisymmetric lens. Zh. Tekh. Fiz. 67, 92–96 (August 1997)     

Chromatic aberrations of thin refractive variable-focus lens

We present an approach to an analysis of the third order chromatic aberrations of thin refractive fluid lenses with a variable focal length. A detailed theoretical analysis is performed for a simple fluidic variable-focus lens and formulas are derived for an optical design of such lenses. Aberration coefficients of the third order of the variable-focus lens can be completely characterized by three parameters which depend only on refractive indices of fluids forming the variable-focus lens. Formulas were derived for the change of the third-order aberration coefficients with the wavelength. Calculations are provided for Varioptic lens Arctic-416.     

多波长广角f-theta透镜光学设计

f-theta透镜作为激光扫描系统中必不可少的部件,对系统工作面尺寸、测量速度、测量精度等起着决定性的作用。为改变以往f-theta透镜扫描范围小、工作波长单一等不足,设计出了一种工作于486 nm~656 nm波段的广角f-theta透镜。通过初级像差分析,确定系统的初级结构参数,利用光学材料的不同色散性能分配合理的光焦度来进行色差校正。设计结果表明:f-theta镜头像散值在像差容限范围内满足平像场要求,f-theta镜头系统最大色差为3 μm,线性畸变误差值不超过0.015%,光能利用率接近90%,聚焦性能接近衍射极限,满足多工作波长、高精度激光打标机的实际需求。     

光学系统纵向色差的仿真及验证

现有的焦距检测方法通常由于检测仪器光源波长与光学系统不完全匹配从而产生纵向色差影响检测结果。针对这一问题,研究光学系统纵向色差的变化规律,并确定在400 nm～1 000 nm波段用于表示其函数关系的Conrady公式和复消色差特性公式。根据光学系统近焦位置的离焦量与位置呈线性关系的特性, 提出使用菲索干涉仪测量5种不同波长的焦距位置,获得单透镜和双胶合镜头的纵向色差曲线。实验结果表明: 在400 nm～1 000 nm波段单色系统和消色差系统的纵向色差的函数关系分别符合Conrady公式和复消色差特性公式,研究结果为焦距的理论计算和精确检测提供了新的思路和参考。     

硫系玻璃在无热化长波红外广角镜头中的应用

设计了一种工作波段为8~12μm、有效焦距为5mm、F数为2、视场角为110°的无热化长波红外广角镜头.根据红外无热化光学设计的基本原理,用了常规红外材料硫化锌、硒化锌和硫系玻璃材料制备的六片镜片,通过合理地分配各个镜片的光焦度以及相互间空气间隔等参量,在全视场角为110°的范围内实现接近衍射极限的成像效果.为了更好地控制系统像差,设计利用了硫系玻璃易于精密模压制备非球面的优点,在两片硫系玻璃镜片上设计了3处非球面.设计结果显示:系统在-40℃~60℃的温度范围内均可实现品质良好的红外成像,光学调制函数全视场内均大于0.4,同时在110°视场角时畸变控制在5%以下;实现了在较大视场角条件下控制红外广角镜头的畸变以及系统无热化等设计要求.该系统体积紧凑、质量较轻,整体设计符合民用红外车载镜头的使用要求.     

Analysis of the healthy rabbit lens surface using MAC Mode atomic force microscopy

In this investigation healthy rabbit crystalline lenses were characterized by atomic force microscopy (AFM). The lenses were cut in slices with thickness with 1mm and thus, put after cortex distinct regions of nucleus and cortex for AFM examination. AFM analysis were carried out using a PicoSPM I operating in Mac Mode. We obtained topographic images of rabbit lenses and a quantitative analysis of the width and height of fibers for nucleus and cortex regions. The longitudinal section analysis of fibers in the nucleus region indicated structures with an average width of 200nm and average height of 200nm. The intershells distance was determined as 4microm. Fiber cell cross-section dimensions, longitudinal and transverse widths, could be estimated in these regions from the AFM images. Structures with average widths as small as 1.0microm are observed in the nucleus; the intershell distance is 4.0microm. In cortical regions, hexagonal structures with average longitudinal and transverse widths of 5.0mum and 3.0mum, respectively, were identified. Three-dimensional images of tissue sections with resolution on a nanometer scale were obtained. The potential of AFM analysis for characterizing healthy and pathologic lens tissues is discussed.     

Aberration invariant optical/digital incoherent systems

We have developed a fundamental technique for control of important known and unknown lens aberrations. Control of lens aberrations through traditional means is very difficult in high-performance optical systems. Minimizing aberrations caused by deterministic design errors as well as statistical fabrication errors has often led to costly systems and fabrication techniques. By employing a special-purpose optical phase mask and digital signal processing we can form imaging systems that are invariant, or substantially insensitive, to a number of important lens aberrations.     

Aberrations theory of a time dependent magnetic field lens

We analyze new forms of aberrations affecting a time dependent magnetic field lens recently proposed. The lens consist of an axially symmetric ellipsoidal solenoid producing a spatially uniform but time pulsating homogeneous field. The dynamics of electrons emitted by some object and injected into this coil shows that this system is capable of focusing a parallel beam or produce images free of geometrical aberrations. The cardinal elements of this lens change periodically in positions and therefore to obtain a stationary image it is necessary to employ a chopped electron beam. Two forms of aberrations originate from the finite duration of the electron pulse and the energy dispersion of the incoming beam (chromatic aberration). Their image degradation effects are quite similar and result from recording different axially displaced images at some fixed stationary plane. We show how, by adjusting the parameters characterizing the magnetic pulse and introducing small apertures that increase the depth of focus, their effects can be reduced or in some cases eliminated. Other forms of instrumental aberrations characteristic of this time dependent magnetic field lens are briefly discussed.