Design of apochromatic telescope without anomalous dispersion glasses

A novel lens system with correction of secondary spectrum without using anomalous glasses is presented. The lens system comprises four separated lens components, with three of them being subapertures. Two examples of apochromatic telescope are presented, both with the use of typical normal glasses, namely crown K9 and flint F5 glasses, and low-cost slightly anomalous dispersion glasses. Secondary spectrum and other chromatic aberrations of the two design examples are corrected.     

基于S-L图的复消色差方法

建立了一组既消位置色差又消二级光谱的方程组,即复消色差方程组.同时引入了规化位置色差系数L和规化二级光谱系数S的概念,得到了对复消色差光学系统设计中的玻璃选择具有指导意义的S-L图.最后给出了应用这种方法进行的三片型透镜组和Petzval型透镜组的复消色差设计过程.     

Optical correlation with totally incoherent light

An optical correlator that can operate with totally incoherent light is presented. Such a correlator can be designed to compensate completely for the inherent chromatic aberrations by resorting to elements with specialized, possibly impractical, dispersion characteristics. Nevertheless, a practical configuration that exploits available achromatic lenses and Fresnel zone plates was designed, built, and tested experimentally. The results reveal that detectable correlation peaks can be obtained with totally incoherent white light. The designs, experimental procedures, and results are presented.     

Hybrid triplet objective with optimum aberration correction

This paper is devoted to the design of a hybrid triplet objective consisting of two refractive lenses and a diffractive element analogous to holographic lens. The possibilities of correcting field aberrations are discussed.Several exemplary solutions of achromatic, apochromatic and quasi-superachromatic hybrid objectives with corrected average field curvature or astigmatism are presented. In the best designs coma is also substantially minimized.     

折衍混合复消色差望远物镜设计的PWC方法

将衍射结构视为折射率无限大的薄透镜,研究了衍射透镜高折射率表示的折衍混合复消色差望远物镜设计的PWC方法;设计了焦距为2000mm、相对孔径为1/15的双片型折衍混合复消色差望远物镜,并与常规三片型纯折射复消色差望远物镜进行了比较,结果表明双片型折衍混合复消色差望远物镜具有更好的二级光谱校正能力,色球差更小,因此具有更好的成像质量.     

Tunable protein harmonic diffractive micro-optical elements

Herein, tunable protein harmonic diffractive microlenses (PHDMs) have been constructed by femtosecond laser direct writing from bovine serum albumin. With excellent three-dimensional topography, PHDMs show distinct harmonic diffractive features, such as similarly good imaging performance with smaller thickness than refractive lenses and well controlled minus chromatic dispersion compared with simple diffractive lenses (～5% focal length shift against ～21% of the protein Fresnel zone plate with the same radius under light with wavelength 450-659 nm). Owing to the nature of protein molecules as "building blocks," the focal length of the PHDM can be facilely tuned within seconds by changing the pH value (focal length tunability of up to ～20%).     

Design of liquid-glass achromatic zoom lens

Optical liquids are ideal materials for designing apochromatic lens due to their lower refractive index and higher Abbe numbers than those of the ordinary optical glasses. Based on the Buchdahl dispersion formula, the dispersion coefficient diagram of liquids and glasses is established. The liquid-glass combination lens(LGCL) with small secondary spectrum is obtained by calculating the combination structure with low dispersion liquid and glasses. The initial optical structure of the liquid-glass apochromatic lens(LGAL) can be obtained by replacing two glass lenses in an initial optical system with the LGCL. Using the multi-configuration optimization of ZEMAX, the liquid-glass achromatic zoom lens (LGAZL) can be designed by optimizing the LGAL. The LGAZL has an objective field of view ?63 mm–?57 mm, an image field of view 8 mm, a working distance 240 mm and the zoom range of focal length 75–85 mm. The chromatic aberration and the secondary spectrum of the LGAZL are all less than 3 μm in the whole zoom range.     

Apochromatic lens combinations: a novel design approach

Apochromatic objectives are constructed by combining three lenses made of different materials with properly chosen powers and dispersions. This paper presents a novel approach to the design of such apochromatic combinations which automatically minimizes the residual chromatic aberration over a specific wavelength range.     

凝视型长波红外折衍混合光学成像系统设计

设计了一套折衍混合凝视红外热成像光学系统.该系统工作波段为8~12 μm, F数为1,全视场达12°, 总长140 mm,两个透镜均采用锗材料。衍射器件制作在第二片透镜的凸面上，可以采用金刚石车削技术进行加工．该系统成像质量接近衍射限并且相对折射系统更好地校正了色差.     

消热差光学系统设计

引入光学材料的规化热差系数T和规化色差系数C,和到对无热差光系统设计的材料选择具有指导作用的T-C图.提出基于热差互补原理的无热差光学系统设计方法,建立了一组既消热差又消色差的方程组.给出了应用这种设计方法设计的密接三片和三分离两种结构型式的无热差系统在不同温度时的像面位移、垂轴像差和各色传递函数曲线.     

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.     

折衍射混合复消色差望远物镜中的色球差

一个正透镜、一个负透镜及一个衍射光学元件以不同的组合可以构成两种折衍射混合光学系统.当这两种系统消球差、彗差及复消色差后会产生不同的色球差.通过赛德尔像差理论,分析了这两种结构产生不同色球差的原因.计算表明当衍射光学元件以负透镜的平面为基底时产生的色球差为以正透镜的平面为基底时产生的色球差的7倍.对衍射光学元件以负透镜的平面为基底的情形,提出了减小系统色球差的解决办法,使系统色球差减小到0.307 mm.另外设计了一个传统复消色差光学系统,并和折衍射混合光学系统进行了比较,分析表明,衍射光学元件可代替传统光学系统中的特殊光学材料并使系统达到相同的成像质量.最后讨论了衍射光学元件的衍射效率对系统成像质量的影响.     

A New Approach to the Design of Hybrid Lenses for Integrated Optics

The Fresnel lens is one of the most extensively studied components in both classical and integrated optics. This structure is free from axial spherical aberration, but is heavily affected by both off-axis and chromatic aberrations. The latter can be compensated by introducing a refractive component, whose chromatic behavior is the opposite of that of the diffractive lens. This hybrid refractive-diffractive structure, however, is not able to deal effectively with off-axis aberrations, namely, with coma. In this work, a novel methodology for the design of corrected hybrid lenses is proposed which allows for correction of both chromatism and coma. The design method is based on a ray-optics variational approach which provides a range of possible achromatic solutions. An optimization procedure is performed by means of a series of beam propagation method numerical calculations which make it possible to simulate the lens operation and thus to find the best solution.     

多波长OCDMA系统频谱效率的改善

分析了色散效应对多波长OCDMA系统频谱效率的影响。在相同的扩频因子条件下,色散效应将降低多波长OCDMA系统的频谱效率峰值,同时达到频谱效率峰值的波长信道数也将相应减少。提出了将前向纠错码用于改善多波长OCDMA系统的频谱效率,分析结果表明,该方案将有效改善多波长OCDMA系统的频谱效率,特别是频谱效率峰值将明显提高。     

用于复色哈特曼人眼波像差测量的折/衍混合调焦系统

设计了一个折/衍混合多色调焦系统,可用于哈特曼波前传感器测量不同波长下人眼的波像差.系统由两片折射透镜和一个二元衍射面构成,焦距调整范围为－200～200 mm.系统性能达到衍射受限,在0.488～0.655 μm波长范围内,焦点色位移小于3 μm.整个系统结构简单、紧凑,同哈特曼波前传感器相匹配,可用于普通人群眼波像差的测量.     

非制冷长波红外热像仪折衍混合双视场光学系统设计

根据衍射光学元件具有大的负向色散特性,将衍射光学元件应用于红外双视场光学系统中,根据傅里叶光学分析衍射光学元件(DOE)的消色差,列表对比折射透镜与衍射光学透镜的特性,并给出变倍比为4∶1可用作非制冷红外热像仪的光学系统的具体设计实例.系统采用切入式变焦方式,在短焦时切入2片透镜实现宽视场,通过引入二元面和非球面提高了成像质量.设计结果表明:在空间频率11 lp/mm处,短焦距40 mm时,各个视场的MTF值均大于0.6;长焦距160 mm时,各个视场的MTF值均大于0.7,宽视场和窄视场都具有较好的成像质量.     

新型平面集成光学相关器设计与分析

基于微光学与二元光学技术,设计了一种新型的平面折叠式光学相关器,将相关器中组成4f系统的傅里叶变换透镜、全息匹配滤波器、输入面和输出集成到一个平面器件上,与另一平面偏振反射镜构成一个反射型的平面光学系统.讨论了相关器的系统结构设计、系统参数的设计,给出了具体的设计模型,计算出其体积可减小至约12 cm3.利用菲涅耳衍射数值模拟方法对系统的图像识别过程进行了仿真,得到了良好的相关输出结果,证实平面集成光学相关器具有很好的识别性能.     

Achromatic doublets using group indices of refraction

One main function of short pulses is to concentrate energy in time and space [1]. The use of refractive lenses allows us to concentrate energy in a small volume of focusing around the focal point of the lens. When using refractive lenses, there are three effects that affect the concentration of energy around the focal point of the lens. These are the group velocity dispersion (GVD), the propagation time difference (PTD), and the aberrations of the lens. In this paper, we study lenses which are diffraction limited so that the monochromatic aberrations are negligible; the group velocity dispersion and the propagation time difference are the main effects affecting the spreading of the pulse at the focus. We will show that for 100-fs pulses the spatial spreading is larger than the temporal spreading of the pulse. It is already known that the effect of spatial spreading of the pulse due to PTD can be reduced by using achromatic optics. We use the theory proposed by A. Vaughan to analyze simple lenses and normal achromatic doublets, where normal means doublets that we can buy from catalogs. We then use the Vaughan theory to design achromatic doublets in phase and group, which produce no spatial spreading of the pulse, i.e., PTD = 0, when the doublet is designed for the carrier of the pulse. We compare these phase and group achromatic doublets with normal achromatic doublets. Finally, we show that apochromatic optics can give a much better correction of PTD than using normal achromatic doublets.     

超高倍变焦光学系统设计

设计了一套焦距f′=8 mm~2 400 mm的超高倍变焦光学系统,对可见光波段成像。采用多组元全动型变焦结构,在实现高变倍比的前提下不增加系统尺寸;在普通衍射透镜的基础上,分析了谐衍射元件的成像特性及色散,减小长焦距所引入的色差和二级光谱;给出了新型非球面方程及特性,解决了普通非球面方程项数选取复杂的问题。在上述理论基础上,利用Zemax光学设计软件对系统进行仿真,引入4个谐衍射面和4个新型非球面。设计结果表明,在奈奎斯特频率50lp/mm时,调制传递函数曲线均在0.5以上,成像质量较好,可广泛应用于军事、航天等领域。     

Wave-front control and aberration correction with a diffractive optical element

A method that permits aberration correction and wave-front reshaping with a diffractive optical element (DOE) is described. Two aligned DOE's made of two different dispersive materials are used. The different dispersions of the two materials in addition to freedom in choosing their thicknesses enables the chromatic aberration and the wave fronts to be manipulated. Design and simulation of such DOE's are described.