Design and experimental study of a planar multibeam double-reflector aplanatic system

The results of design and experimental investigation of a multibeam planar three-layer double-reflector system in the millimeter wave band are presented. A Schwarzschild aplanatic reflector system with symmetric generatrices is considered. The system parameters have been chosen as a result of optimization of this system with the use of the method of physical optics and the Pareto criterion. A prototype of an integral quasi-optical system in the form of a multilayer printed circuit board containing an aplanatic double-reflector optical system illuminated by an array of 19 microstrip horns has been manufactured. Experimental studies have been performed at a frequency of 36 GHz; a set of beams with fan-shaped radiation patterns in a coverage sector of ±38° has been obtained. The experimental data are compared to the results of calculation.     

Eikonal aberrations in planar double-reflector antennas

A formula describing the eikonal distribution on the main reflector of a 2D double-reflector system is derived for an arbitrary direction of the offset of the source from the focus, the second focus being at infinity. The formula takes into account four terms of the expansion of the eikonal in the powers of the offset of the source. The accuracy of the formula is analyzed by comparing the results of calculation of the eikonal in a 2D Schwarzschild system with the exact geometric-optics calculation. Formulas for the focal curve, the phase front inclination angle, and aberrations in an arbitrary double-reflector telescopic system are obtained. The formula obtained is used for the analysis and minimization of aberrations in a 2D Schwarzschild system.     

Eikonal Distribution on the Surface of an Axisymmetric Dielectric Lens and Minimization of Aberrations

On the basis of the one-parametric theory of aberrations developed in the paper, a formula is obtained that describes the eikonal distribution on the surface of an axisymmetric dielectric lens with two focuses arbitrarily located on the axis and a source displaced from the focus in an arbitrary direction. The error of the formula is of the fourth order of the source displacement. A numerical analysis of the accuracy of the obtained formula and its expansions is performed by comparing the results of the eikonal calculation and the magnitude of aberrations on the surface of an aplanatic lens with the results of the exact geometrical optics calculation. The equation of the focal curve and the condition for the minimum of astigmatism are obtained. As an example of application of the formulas found, a wide-angle aplanate-anastigmat with optimal parameters is synthesized. The scanning characteristics of a lens antenna based on the synthesized aplanat-anastigmat are analyzed in the physical optics approximation.     

On eikonal aberrations in axisymmetric double-reflector telescopic systems

A formula describing the eikonal distribution on the surface of the main reflector of a doublereflector system of a general form is derived and its expansion in powers of the offset of the source from the focus up to the fourth-order terms is obtained. The analysis and minimization of aberrations for a doublereflector aplanatic Schwarzschild system are performed.     

Chromatic and spherical aberration correction for silicon aplanatic solid immersion lens for fault isolation and photon emission microscopy of integrated circuits

Current state-of-the-art in backside fault isolation and logic analysis utilizes solid immersion lens (SIL) imaging in the central configuration. An attractive advancement is the development and integration of an aplanatic SIL, which allows significant improvement in resolution, signal acquisition and isolation capabilities, especially for the 22 nm node and beyond. However, aplanatic SIL configurations introduce both chromatic and spherical aberrations. We have developed backing objective designs capable of correcting for chromatic aberrations allowing application in photon emission microscopy, as well as deformable mirror designs and experiments that eliminate spherical aberrations of aplanatic SILs to account for variations in substrate thickness and off-axis imaging.     

Design of aplanatic waveguide Fresnel lenses and aberration-freeplanar optical systems

A modification of the waveguide Fresnel lens design that has phase-shifting zones placed on the curved contour is suggested. It is shown that the selection of a suitable shape for this contour allows coma aberration to be eliminated. Computer simulation results are presented to demonstrate the significant improvement of the optical characteristics for curved contour lenses. The aplanatic homogeneous refracting waveguide lenses are also considered. It is found that thick aplanatic refracting lenses and the proposed Fresnel lenses have field curvature aberration of opposite sign. This fact allows planar optical systems free from low-order aberration to be designed by combining refracting and Fresnel lenses. An algorithm for producing such a system is presented     

一种基于Shack-Hartmann传感器的自适应波前重建算法

波前重建是自适应光学系统中的一个重要环节,对系统性能影响明显。研究了一种无参考输入光条件下,基于Shack-Hartmann波前传感器的自适应波前重建算法,能根据实际光斑图的特点,自动确定探测窗口、计算实际质心、参考质心、选择重建区域和获取入射波前的Zernike模式系数,讨论了参考质心选择对波前重建结果的影响。搭建自适应光学系统,通过测量和校正模拟大气像差对重建算法进行了验证。实验结果表明,基于该重建算法的自适应光学系统可以把大气扰动引起的波前像差校正到0.1 λ以下,获得接近衍射极限的成像质量,说明该重建算法具有可靠性与实用性。     

On aberrations of eikonal in planar lens antennas

A formula for the eikonal distribution over the surface of a cylindrical dielectric lens with an error on the fourth-order of the displacement of the source from the focus is found. The accuracy of this formula and the first three terms of its expansion in this parameter for describing the eikonal and its aberrations are analyzed. A method for finding the parameters of the optical aplanatic lens (with minimum aberrations) is proposed. An approximate equation of the focal curve is derived.     

Designing Schwarzschild dual-reflector systems

The purpose of this paper is to provide readers an easy set of equations and design parameters to generate Schwarzschild dual-reflector systems. We consider the geometry of a Schwarzschild dual-reflector system, consisting of two rotationally symmetric reflectors, which form an aplanatic system that fulfills the Abbe sine condition. This dual-reflector system ensures freedom from spherical and primary coma aberrations when the feed horn is displaced from the axis of symmetry. This is a useful property for beam-scanning or multibeam applications.     

Optimization of multilayer integrated optics waveguides

A numerical method is described that provides the means for optimizing any objective function representing a general multilayer integrated optics waveguide. In this way, the physical parameters of the multilayer structure can be set so that the performance of the device is optimized. The method uses any standard numerical minimization algorithm in conjunction with the argument principle method. The method has been successfully applied for the optimization of a multilayer immunosensor and a TE-mode polarizer. The advantages of the method are its generality, its efficiency, its accuracy, and its applicability to a wide range of planar integrated optics devices     

Even aberration measurement of lithographic projection system based on optimized phase-shifting marks

In the present paper, we propose a novel method for measuring the even aberrations of lithographic projection optics by use of optimized phase-shifting marks on the test mask. The line/space ratio of the phase-shifting marks is optimized to obtain the maximum sensitivities of Zernike coefficients corresponding to even aberrations. Spherical aberration and astigmatism can be calculated from the focus shifts of phase-shifting gratings oriented at 0°, 45°, 90° and 135° at multiple illumination settings. The PROLITH simulation results show that, the measurement accuracy of spherical aberration and astigmatism obviously increase, after the optimization of the measurement mark.     

无波前传感自适应光学技术及其在大气光通信中的应用

无波前传感自适应光学(AO)系统不依赖波前传感器可直接对系统性能进行优化。基于随机并行梯度下降(SPGD)算法,32单元变形镜,CCD成像器件等建立了无波前传感自适应光学系统实验平台。实验结果表明,参量选取合适时,系统对畸变波前具有较好的校正能力,但受限于较低的CCD采样频率,仅能校正静态或缓慢变化的像差。根据实验结果讨论了基于随机并行梯度下降控制算法的无波前传感自适应光学技术在大气光通信中的应用可能和应用方法,指出采用高速光电探测器件、高速数据处理及响应速度高的波前校正器与随机并行梯度下降算法相配合可用于补偿大气光通信中的大气湍流扰动。     

Capacity analysis of a simple integrated planar optical interconnects system

The analysis of capacity in a simple integrated planar optical interconnects (IPOIs) system, based on the Gaussian propagation model, is presented. The interconnects capacity is obtained as a function of signal-to-noise ratio (SNR), optical signal power, optical noise power, electrical noise equivalent power, and the geometrical constraints of the concept of integrated planar optics (IPO). The dependence of interconnects capacity on various system parameters is analysed and simulated. It is shown that the design of the IPOIs system can be optimized for maximum capacity using geometrical constraints as design parameters.     

基于渐近解的成像电子光学近轴横向像差理论及其验证

在成像电子光学系统的横向像差中,近轴像差是整个像面普遍存在、且影响图像中心像质的主要像差,并决定了系统的极限分辨率.本文由电子光学近轴方程的渐近解推导了近轴横向像差的普遍表示式,并通过一两电极静电同心球系统,推导了近轴轨迹特解的渐近解和精确解的解析表示,给出了二级和三级近轴色球差以及三级近轴放大率色差的表达式,证明了基...     

自适应光学高分辨率共聚焦显微成像技术

生物样品折射率的空间变化导致了光学畸变的产生,这种畸变对于共聚焦显微镜观察厚的生物样品和活体体内组织成像是一种严重的限制。自适应光学(AO)技术是通过快速反应的变形镜使镜面发生形变来补偿像差,在共聚焦显微镜中应用自适应光学技术可以校正光学畸变,观察深层组织活动,进行活体成像和实时检测。详细分析了共聚焦显微镜中像差的来源及光学畸变的特点,讨论了目前在共聚焦显微镜中自适应光学校正的方案及研究现状,讨论了共聚焦显微镜中自适应光学的波前传感器、畸变测量和波前校正器,并探讨了目前超高分辨率显微成像技术的发展方向。     

Resonant scattering from a conducting cylinder clad with an anisotropic plasma

The scattering of an electromagnetic wave from a conducting cylinder clad with an anisotropic plasma of arbitrary electron density is considered, and the eigenfunction solution is obtained. The resonant behavior of the system is investigated. The resonant conditions are obtained, and damping of the resonant scattering by finite size effects and collisional dissipation is studied. The Rayleigh and geometrical optics limiting cases are derived, and the approach of the plasma scattering to that from a metallic body for increasing plasma frequency (electron density) is obtained. Comparisons with the scattering from an unclad cylinder and from a planar conductor sheathed with a plasma are made.     

Maxwell鱼眼微球透镜对有限远物点的成像及其像差

本文在文献［１］的基础上用变折射率介质中的光线理论研究了Ｍａｘｗｅｌｌ鱼眼球透镜对有限远物点成像的可能，导出了它对有限运物点的像距和纵、横向球差的计算公式。数值计算的结果表明该种球透镜不仅可以对有限远物点成像，且其纵、横向球差甚小．若合适选取透镜的参数，其纵、横向球差可比均匀折射率球透镜小两、三个数量级，在短物距时也比自聚焦棒透镜小。从而进一步显示了它在集成光学和微型光学系统中应用的可能性。     

电磁复合场三级几何像差方程的修正与像差系数

本文基于作者提出的“函数逼近的数值迭代概念”，修正了电磁复合场中电子成像系统的三级几何像差方程式，给出了具有更高精度的像差计算公式和用集中参数形式描述的像差系数表达式，为像差的数值计算和电子光学系统的计算机优化设计提供了实用的理论依据。     

墙壁散射对超低副瓣天线平面近场测量的影响

以二维问题为例，基于平面波谱展开理论和几何光学近似，利用计算机模拟的方法研究了暗室墙壁散射对超低副瓣天线平面近场测量的影响，得到了一些基本的规律和有用的结果。     

基于随机并行梯度下降算法的望远镜静态像差校正

为校正大口径量子通信望远镜的静态像差,提高接收信号光的能量集中度,提出了基于随机并行梯度下降(SPGD)算法的静态像差校正方法。该方法不同于经典的自适应光学校正方法,无需波前传感器,可有效降低系统的复杂性。对SPGD算法进行了分析,在此基础上利用64单元变形镜和CCD探测器搭建了校正平台,并将该校正平台应用到青海湖量子通信地面站望远镜系统,对700mm望远镜的静态像差进行了校正,远场光斑直径由校正前的58μm改善为30μm,验证了SPGD算法对望远镜波前畸变校正的可行性。