Study of Anisotropy Effect in Planar Lenses for Integrated Optics

Abstract

The extraordinary-ray ray-tracing method for planar waveguides on uniaxial crystals is developed. Using the method and the extended equivalence principle, the effect of anisotropy on the performance of planar lenses is investigated in detail. The agreement between theoretical and experimental results is very good.     

光测设备天文标校单项误差分离算法

为实现船载光测设备的经常化检查校准,针对影响天文标校工作成败的诸关键要素,在理论分析的基础上进行了试验研究.首先对天文标校方法硬件原理、软件组成、工作流程进行介绍,然后重点对设备误差分离算法进行分析,首次提出了基于奇异值分解的误差方程解算方法,最后给出了试验研究的一组典型数据.标校试验结果表明:该标校方法可以实现8项单项误差的成功分离,关键项多次标校数据重复性小于等于±1",使设备实际测角精度提高1倍,并优于常规标校的设备精度.     

Optical Beam Induced Currents: Investigations of Integrated Circuits Using Different Excitation Wavelengths

Abstract

A laser scanning microscope with different laser wavelengths is used to investigate internal binary states and diffusion parameters of integrated circuits. With blue laser radiation the internal logical levels in the integrated circuits could be detected. Red and i.r. radiation are used to investigate the depth and location of doped wells. Applying three wavelengths could distinguish between surface and bulk recombination.     

平面光波导自动耦合控制系统的实现及测试

开发了新的自动对接方法,设计了基于阈值的折返遍历搜索算法(RTS)与二分数据截断(BTDT)搜索算法,实现了六自由度耦合平台的四自由度的自动对接。折返遍历搜索算法精度高,可设定不同步长实现不同精度要求;二分数据截断算法搜索速度快,可快速接近最高点。实验结果表明,波导器件的纤到纤损耗可在8 min内调节至8~9 dB(包括波导传输损耗,人工对准需在半小时以上才可达到8~9 dB),耦合系统稳定性可保持15~20 min。与自动测试系统配合使用,在8 min内即可进行2 200点的波长扫描与功率扫描,自动耦合系统具有实用性、稳定性和良好效果。     

Knife Gauge for Measurement of the Intensity Distribution in a Beam of Optical Radiation

A method of measuring the distribution of the intensity of optical radiation in space is described. The method consists in measurement of the power reflected from a specially shaped knife that moves perpendicular to the direction of propagation of the beam or that passes through a moving diaphragm provided with a hole.     

Molecular Engineering of Peripherally And Axially Modified Phthalocyanines for Optical Limiting and Nonlinear Optics

Phthalocyanines have remarkable chemical and thermal stability and offer tremendous architectural flexibility in their structure, facilitating the tailoring of physical, optoelectronic, and chemical parameters. In this paper, we summarize experimental measurements of nonlinear optical absorption in a comprehensive representative series of modified phthalocyanines substituted with various central metals and peripheral functional groups. Rate equations are used to analytically solve the static‐state conditions that simulate the excited‐state dynamics that result from the nonlinear excited‐state absorption, and this solution is fitted to the experimental data. General molecular engineering trends relating the optical limiting performance of these compounds to their structural characteristics are also explored and discussed.     

Integrated Population Balance Model Development and Validation of a Granulation Process

This study is concerned with the development of an integrated three-dimensional population balance model (PBM) that describes the combined effect of key granulation mechanisms that occur during the course of a granulation process. Results demonstrate the importance of simulating the different mechanisms within a population balance model framework to elucidate realistic granulation dynamics. The incorporation of liquid addition in the model also aids in demarcating the dynamics in different regimes such as premixing, granulation (during liquid addition) and wet massing (after liquid addition). For the first time, the effect of primary particle size distributions and mode of binder addition on key granule properties was studied using an integrated PBM. Experimental data confirms the validity of the overall model as compared to traditional models in the literature that do not integrate the different granulation mechanisms.     

光学元件离子束修形去除效率分析

离子束修形(IBF)技术成为光学零件获得超高面形必不可少的加工工艺.修形过程中采用光阑获取小的束径、稳定的去除函数是获得超高面形精度的前提.不同材料和工艺参数等不同条件下获得的去除函数都不相同,每次修形前都要重新测量去除函数.研究了不同入射能下、不同靶距下以及有无光阑时去除函数的变化.发现在离子光学系统几何参数一定的条件下,离子束去除函数的效率变化与入射能量、离子体浓度引起的离子鞘形状、束散角、温度、靶距、净加速电压与总加速电压之比的变化等因素都有关.当增大入射能量时,去除效率随之增加,但当入射能量大于一定值后就会出现随着入射能量增加而去除效率降低的"拐点"现象.有无光阑只改变去除效率的大小而不会改变"拐点"现象.因此不选用入射能量增大而去除效率减小的"拐点"之后的入射能量修形.     

The Optical Effects of a Double Calcite Plate on a Converging Beam of Light

The aberrations and variation in transmission of a beam of light converging to a focus and passing through plates of calcite have been investigated, in order to estimate possible photometric errors due to these effects when a crossed calcite plate is used to calibrate photographic plates. The aberrations are calculated in terms of ray deviations whose magnitudes are derived, and the transmission coefficient is determined by solution of electromagnetic boundary conditions. The resultant formulae are evaluated numerically, and set limits on the photometric accuracy of images formed by a Schmidt telescope used with a calcite plate calibrator.     

高斯光束到光纤的单透镜耦合

分析了基模高斯激光束到单模和多模光纤的单透镜耦合过程中的各种损耗,把多模光纤的光场用高斯分布近似,采用模场耦合理论计算了基模高斯光束到单模和多模光纤的单透镜耦合效率.模拟计算了当激光-光纤耦合系统的工程参数(光束束宽、光纤数值孔径和光纤的纤芯芯径)一定时,单透镜耦合效率与所选用透镜的焦距之间的关系.并利用532mn激光(M2≤1.05)在几种不同焦距的透镜下对纤芯直径为3.μm的单模光纤和25μm的多模光纤进行了耦合效率的测定实验,得到了与理论计算基本吻合的实验结果.     

Optics Concept for a Pair of Undulator Beamlines for MX

We describe a concept for x-ray optics to feed a pair of macromolecular crystallography (MX) beamlines which view canted undulator radiation sources in the same storage ring straight section. It can be deployed at NSLS-II and at other low-emittance third-generation synchrotron radiation sources where canted undulators are permitted, and makes the most of these sources and beamline floor space, even when the horizontal angle between the two canted undulator emissions is as little as 1-2 mrad. The concept adopts the beam-separation principles employed at the 23-ID (GM/CA-CAT) beamlines at the Advanced Photon Source (APS), wherein tandem horizontally-deflecting mirrors separate one undulator beam from the other, following monochromatization by a double-crystal monochromator. The scheme described here would, in contrast, deliver the two tunable monochromatic undulator beams to separate endstations that address rather different and somewhat complementary purposes, with further beam conditioning imposed as required. A downstream microfocusing beamline would employ dual-stage focusing for work at the micron scale and, unique to this design, switch to single stage focusing for larger beams. On the other hand, the upstream, more highly automated beamline would only employ single stage focusing.     

平面光波导膜的ECR-PECVD制备及特性研究

采用微波电子回旋共振等离子体增强化学气相沉积技术 ,在单晶硅衬底上制备了用于平面光波导的SiO2 薄膜 ,研究了沉积速率与工艺参数之间的关系 ,并对射频偏置对成膜特性的影响作了初步实验研究。通过X射线光电子能谱、傅立叶变换红外光谱、扫描电镜、原子力显微镜、以及扫描隧道显微镜三维形貌和椭偏仪等测量手段 ,分析了样品的薄膜结构和光学特性等。结果表明 ,在较低温度下沉积出均匀致密、性能优良的SiO2 薄膜。此外 ,还成功制备出掺Ge的SiO2 薄膜 ,并可以精确控制掺杂浓度 ,以适应不同光波导芯的要求     

高能激光束在线测量系统的光取样器研制

针对环形光刀取样式高能激光光强分布测量系统的要求,研制了以圆弧反射面环形光刀架构的光取样器,实现了对激光束的在线取样测量。光取样器的取样光刀外形设计为环形光刀,可对取样光束进行周向扩展,满足半数以上探测器接收取样空间光信号的要求;取样光刀反射面设计为圆弧形,可对取样光束进行切向扩展,使其在增大衰减倍率的同时降低系统对光的难度。通过光取样器具体设计参数的计算,获得了满足探测单元与反射光束耦合孔径角要求的参数设计范围。实验表明,研制的光取样器可有效用于大面积高能激光束的在线测量。     

束状光波大气传输源象抖动时间频谱

本文研究了通过湍流大气传输束状光波在接收光学系统象面上成象位置抖动方差和抖动时间频谱。得到了包含风速因子υ_⊥且适用于全部湍流起伏区的抖动方差和象点抖动频谱的一般关系式。     

On the Global Efficiency of the Laser Optical Excitation of a Fast Atomic Beam

Abstract

The interaction of a fast atomic beam and a laser beam that crosses at right angles has been considered. We have studied the competition between the Doppler effect, due to the angular divergence of the atomic beam and the effect of the laser light intensity distribution. For low laser power values, an optimum waist size can be determined. For higher laser power values, the conditions for a maximum global efficiency are outlined.     

Propagation of a Gaussian Beam in Planar and Cylindrically Inhomogeneous Media: Comparison of Modal Analysis and Approximate Approaches

This work presents a study on the propagation of electromagnetic waves in media, characterized by k = k₀ m k₂ y ² and k = k₀ m k₂ r². A vector theory based on Maxwell's equations is used to derive linear homogeneous second-order equations satisfied by the transverse electric and magnetic field components. The various modes of propagation and the corresponding propagation constants have been determined. These are used to study the propagation and focusing of waves which have an intensity distribution along their wavefront. An alternative method for the study of the propagation and focusing of electromagnetic waves has been discussed. This is based on an approximate solution of the wave equation given in previous communications. For parameters of interest, the results obtained from the approximate solution are in excellent agreement with the solution obtained from the modal analysis of the problem. The present study should be of relevance in tropospheric communication and focusing of laser beams in selfoc fibres, gas lenses, etc.     

Angular momentum of the fields of a few-mode fiber. III. Optical Magnus effect, Berry phase, and topological birefringence

It is shown that, on the one hand, the evolution of the angular rotation of the lines of nodes of the CP₁₁ mode is a manifestation of the optical Magnus effect in a few-mode fiber with a parabolic refractive index profile, and, on the other hand, the additional phase γ _b =±δβ ₂₁ z in CV and IV vortices is the Berry topological phase, which arises as a result of the cyclic change in the orientations of the orthogonal axes of dislocations. The splitting of the propagation velocities of orthogonal circularly polarized CV⁺ and IV⁻ modes in an LV vortex in a parabolic fiber is a manifestation of the phenomenon of topological birefringence of a few-mode fiber. The azimuth of the linear polarization of a vortex undergoes continuous angular rotation. In an optical fiber with a stepped index profile the CP₁₁ mode forms circularly polarized edge dislocation over lengths which are multiples of half the beat length, and over lengths which are odd multiples of the quarter beat length it forms linearly polarized fields with a purely screw dislocation. This transformation of edge and screw dislocations can be regarded formally as conversion of the polarizational angular momentum into orbital angular momentum. The conversion of angular momentum is a reflection of the dynamical unity of the optical Magnus effect and the Berry topological phase in the fields of a few-mode fiber. Pis’ma Zh. Tekh. Fiz. 23, 59–67 (December 12, 1997)