A lens hologram technique for analysing symmetrical aberrations of a camera system

A holographic technique is described whereby a 35 mm camera lens is used in conjunction with its own film to measure focusing errors and other symmetric aberrations. The method relies on photographing a scatter-plate whose fabrication is described. Results are presented showing how four different camera systems perform at various field angles.     

像差对星敏感器星点定位精度的影响

光学系统星点定位精度是表征星敏感器性能的一个重要指标,像差对该精度有一定影响。分析光学系统像差对星点定位精度的影响,在计算典型中等精度星敏感器光学系统星点定位误差的基础上,提出用实际测得的星点光斑能量质心位置计算理想位置的误差补偿新方法。计算结果表明:像差对高精度(如角秒级)星敏感器姿态测量精度的影响不可忽略;采用星点定位误差补偿后,星敏感器三轴姿态测量误差RMS值分别为0.38″,0.38″,5.77″,仅为原来的1/17。     

制作工艺误差对X射线组合折射透镜聚焦性能影响研究

本文主要介绍对X射线组合折射透镜的制作工艺误差对其聚焦性能影响的研究结果. 首先给出采用深度X射线光刻技术制作的PMMA材料圆柱面型X组合折射透镜的工艺测试结果,得出制作工艺误差值,定性分析制作工艺误差对X射线组合折射透镜聚焦性能的影响. 然后根据实际的制作工艺误差建模,给出详尽的理论分析和定量的理论模拟结果. 最后在北京同步辐射装置(BSRF)上,构建基于PMMA材料的圆柱面型X射线组合折射透镜的微束聚焦实验系统,实际测试了有明显工艺误差和尽量消除工艺误差的两种X射线组合折射透镜的聚焦性能,给出实测结果 关键词： X射线组合折射透镜 制作工艺误差 X射线聚焦性能 同步辐射     

Compensation for chromatic aberrations in acousto-optic systems used in spectral analysis of images

This paper considers novel optical schemes that are related to acousto-optic systems for the spectral analysis of images. The systems are characterized by a low level of transverse and longitudinal chromatic aberrations. Mathematical expressions that describe the magnitudes of the transverse aberration in various configurations of acousto-optic filters are derived. A decrease in longitudinal chromatic aberrations is examined in an optical scheme that is based on a single objective lens and an additional negative lens. A similar analysis is carried out for a confocal system that is formed of two objective lenses. The experimental investigations carried out in the visible range of the spectrum demonstrated a decrease in the longitudinal shifts of images by a factor of 2.5 and by as much as two orders of magnitude or more in the transverse image shifts.     

Exploring fabrication tolerances of optical systems by solving inequalities

A scheme to study fabrication tolerances of optical components and systems is presented. By solving a set of non-linear inequalities an optimal set of lens parameters is found. Then, by selecting another, but strict, set of boundaries to the non-linear inequalities system, a new set of lens parameters is found. The fabrication tolerances are determined by the intersection domain of each lens parameters obtained by solving the set of non-linear equations, with a condition that one solution should come from a strict set on boundaries of the non-linear equation system. This scheme is applied to a classical triplet lens system, used as starting point, and is compacted in effective and back focuses lengths, showing the versatility to study the fabrication tolerances.     

泽尼克多项式校正全息阵列光镊像差的实验研究

像差会影响光镊对粒子的捕获效果. 全息阵列光镊中, 像差不仅来自光学元件, 由特定算法设计的光阱相位片也会在光路中引入像差. 本文通过液晶空间光调制器加载泽尼克多项式相位图, 对全息阵列光镊中由光栅透镜组型算法引起的像差进行校正. 结果显示: 利用三阶泽尼克多项式可有效消除光路中由光栅透镜组型算法引 起的慧差, 使得捕获2 μm聚苯乙烯小球的阵列光阱刚度提高了约40%; 对比不同项的像差校正结果发现, 全息阵列光镊中由算法引起的慧差 与光学元件引起的像差一样, 也会对阵列光阱的捕获效果产生较大影响; 同时根据一阶像差校正结果可得光栅透镜 组型算法对于一阶泽尼克像差具有鲁棒性. 实验结果表明, 对全息阵列光镊中由 算法引起的像差进行校正, 对于提高光阱的捕获效果和深化对算法特性的认识都具有重要意义.     

二元光学透镜在资源卫星中的应用

使用一种基于二元光学透镜的分光成像及消色差原理的新方法来设计资源卫星的中继光学系统。通过分析二元光学透镜的分光成像原理、消色差原理、衍射效率与阶数和工作波长及设计波长的比之间的关系,又考虑到单独设计制造二元光学透镜的难度,采用折衍混合成像光学系统来拟定资源卫星中继光学系统的设计方案,给出用ZEMAX软件设计的具体结果。设计实例及分析结果表明,包含二元光学透镜的折衍混合成像系统可以很好的实现光谱波段分离,用于资源卫星的光学系统具有一定的适用性。     

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.     

Perfect imaging of hypersurfaces via transformation optics

Conventional optical imaging systems suffer from the presence of many imperfections, such as spherical aberrations, astigmatism, or coma. If the imaging system is corrected for spherical aberrations and fulfills the Abbe sine condition, perfect imaging is guaranteed between two parallel planes but only in a small neighborhood of the optical axis. It is therefore worth asking for optical systems that would allow for perfect imaging between arbitrary smooth surfaces without restrictions in shape or extension. In this Letter, we describe the application of transformation optics to design refractive index distributions that allow perfect, aberration-free imaging for various imaging configurations in R(n). A special case is the imaging between two extended parallel lines in R(2), which leads to the well-known hyperbolic secant index distribution that is used for the fabrication of gradient index lenses.     

Contributions of the cornea and the lens to the aberrations of the human eye

The relative contributions of optical aberrations of the cornea and the crystalline lens to the final image quality of the human eye were studied. The aberrations of the entire eye were obtained from pairs of double-pass retinal images, and the aberrations of the cornea were obtained from videokeratographic data. Third-order spherical aberration and coma were significantly larger for the cornea than for the complete eye, indicating a significant role of the lens in compensating for corneal aberrations. In a second experiment retinal images were recorded in an eye before and after we neutralized the aberrations of the cornea by having the subjects wear swimming goggles filled with saline water, providing a direct estimate of the optical performance of the crystalline lens.     

A method to accurately control the period of subwavelength planar holographic grating in the fabrication process of guided mode resonance filter

Subwavelength optical element such as guided-mode resonance filter has gained much interest recently due to its properties and applications. It is very hard to fabricate an ideal guided-mode resonance filter with the same parameters as the designed one. The reason is that the resonance wavelength of guided-mode resonance filter is susceptible to the fabrication errors of its parameters, such as the period, the groove depth, the thickness of a guided-wave layer, and the refraction indexes of materials, etc. In this article, a method to accurately control the period of subwavelength planar holographic grating which was used as a sub-layer of the guided mode resonance filter is investigated. Results show that utilizing a convex lens placed in the exposure position can cause the adjusting of the period of subwavelength planar grating more convenient in the holographic optical path during the fabrication process. Accuracy controlling the period of grating which was used as the sub-layer of guided-mode resonance filter has great significance in the fabrication of guided-mode resonance filter.     

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.     

Nanocomposite‐based stretchable optics

Stretchable and conformable optical devices open up very exciting perspectives for the fabrication of systems incorporating diffracting and optical power in a single element. Supersonic cluster beam implantation of silver nanoparticles in an elastomeric substrate grooved by molding allows effective fabrication of cheap and simple stretchable optical elements able to withstand thousands of deformations and stretching cycles without any degradation of their optical properties. The nanocomposite‐based reflective optical devices were characterized both morphologically and optically showing excellent performances and stability compared to similar devices fabricated with standard techniques. The nanocomposite‐based devices can therefore be applied to arbitrary curved nonoptical grade surfaces in order to achieve optical power and to minimize aberrations like astigmatism. The high resilience of the nanocomposite material on which the devices are based allows them to be peeled and reused multiple times.     

计算全息法测量长焦透镜面形和焦距

为了同时对长焦透镜的面形和焦距进行高精度检测,提出在Zygo干涉仪的球面光路中加入一个二元衍射元件作为检测件的计算全息法。 首先对计算全息法检测长焦透镜的面形和焦距进行了理论推导,并给出焦距误差公式。在Zemax中使用在平面基底上制作的二元衍射元件对一个长焦透镜的面形和焦距进行了模拟检测,其中对该长焦透镜面形的干涉检测PV值为0.0034λ,对焦距的检测精度为-0.11%。最后详细分析了两类误差对检测结果的影响,其中光学元件的位置误差影响不超过0.1λ;二元衍射元件的制造误差影响约0.01λ,在具体制造过程中,其径向位置误差和台阶误差可分别在2 μm和5 nm之内。在综合考虑各项误差的情况下,该方法的检测精度仍然可控制在2λ/25之内。     

光学系统的偏振像差分析

偏振像差是影响光学系统性能的重要因素之一,尤其对偏振有严格要求的光学系统来说更是如此。论述了偏振像差的理论和偏振光线追迹的方法,并对旋转对称光学系统、倾斜偏轴光学系统的偏振像差进行了分析,指出了薄膜设计对偏振像差所产生的重要影响。介绍了提高光学系统偏振精度的几个方法,包括尽可能的减小入射角、薄膜设计的优化和像差之间的相互平衡。     

光电设备中球罩的视轴误差研究

光学窗口是光电设备中必不可少的光学元件,对处于大视场成像或全方位扫描工作模式的光电系统,常采用曲面形式的同心球罩作为光学窗口。球罩加工过程中的球心偏差和装配过程中与光电系统入瞳中心的偏差都会对光电系统的视轴角度带来误差。推导了球罩加工、装调误差对光电系统视轴影响的数学表达式,分析了各误差对光电系统视轴的影响,得到了球罩的各误差环节对光电系统视轴影响的规律,对球罩的设计和在光电系统中的使用具有重要的意义。     

A Spectrometer Based on Diffractive Lens

A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.     

A Spectrometer Based on Diffractive Lens

A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.     

Study on differential algebraic method for electron optical properties of wide electron beams in immersion electrostatic-magnetic lenses

Differential algebraic method for calculation of electron optical properties is extended to wide electron beams in combined immersion electrostatic-magnetic lenses, based on Taylor series expansion of the differential algebraic data structure of wide electron beam focusing systems. Higher order aberrations referred to off-axis central trajectories are calculated and this makes the evaluation of wide electron beam focusing properties much simplified with high-enough precision. A program was written, and a specific combined immersion electrostatic-magnetic lens is calculated as an example. Computed results show that the second aperture aberrations referred to off-axis central trajectories of the system of the primary one, whereas the third- and over third-order ones only play a secondary role.