纳米分辨近场光学显微成象技术现状

介绍了纳米分辨近场光学显微成象技术现状,近场光学显微成象技术大体可分为小孔扫描近场光学显微镜（Ａ－ＳＮＯＭ）、无孔径用射扫描近光学显微镜（Ｓ－ＳＮＯＭ）和光子扫描隧道显微镜（ＰＳＴＭ）三种基本类型,除介绍这三类近场光学显微镜简要成象原理、现状和各自特点外,还重点介绍了大连理工大学纳米成象技术研究组ＰＳＴＭ的研究进展,即ＰＳＴＭ消假象数值模拟和实验研究结果,其实验空间分辨首次达到２．８ｎｍ线扩展函数     

高密度近场光学存储技术的发展

引言与传统光学提高透镜数值孔径、缩短光波长的思路不同,近场光学提高光学分辨率和存储密度是基于完全不同的原理。近场光学显微术基于隐失波探测及局域场中隐失波与物质相互作用的原理,光学分辨率与波长无关,突破了经典光学中分辨率衍射极限,达到纳米量级,使光学分辨率提高了几十倍甚至上百倍。近场光学理论研究涉及纳米尺度光波的物理特征与现象,如隐失波的分布、局域场增强、非传播场转换等。国际学术界明确提出近场光学是光学通向纳米科学技术的桥梁。     

飞行光学头飞行性能计算机仿真

研究与设计飞行光学头是推出新一代高密度近场光记录光盘驱动器的关键技术之一 .为了灵活方便地对各种结构形式的光学头进行飞行性能分析 ,本文在对飞行光学头进行建模与分析的基础上 ,在 Matlab环境下开发出了飞行光学头飞行性能分析软件 ,给出了飞行光学头的仿真建模及性能分析软件系统的设计思路和总体规划 .     

水声换能器近场校准方法的实验研究

近场校准方法可用于在近场条件下校准水声换能器。方法以亥姆霍兹(Helmholtz)积分为基础,由近场测量数据推算大尺寸水声换能器的远场特性。本文叙述了三种不同类型换能器近场数据测量技术和远场特性计算方法,并作为例子给出了近远场校准结果。     

复杂目标的近场RCS估算

为了预估复杂目标的近场雷达散射截面(RCS),通过图形电磁计算方法(GRECO)来求得复杂目标远场散射中心的雷达散射截面,采用z-buffer遮挡消隐技术来提取面元远场散射中心的位置,然后给出一种预估复杂目标近场RCS的方法.在雷达天线与目标之间的距离不是太近的情况下,通过仿真目标的远场和近场RCS的分布情况,并对其结果进行比较分析.可以证明该方法计算出来的近场RCS是有效的、准确的,可以应用到实际工程中去分析和解决问题.     

天线在近场测量中的卷积外推算法研究

针对暗室难以满足大尺寸高频率天线测量的远场条件,为提高精度,加强保密特性,提出了一种由天线近场卷积外推到远场的算法。大尺寸高频率天线的纵向尺寸较小时,可将其辐射的球面波可近似成柱面波,对其进行柱面波基函数展开,经过严格的理论推导最终建立起近场与远场的卷积外推关系,从而实现利用天线近场的测量数据快速获得远场方向图特性。利用MATLAB软件对算法进行数学仿真分析并证明其有效的基础上,对导航天线在近场进行了实际测量。最终对所测数据进行卷积外推,得到的方向图与天线远场方向图基本吻合,从而验证了该算法的可靠性,具有一定的实用价值。     

一种新型近场光盘光学头设计的仿真研究

近场光盘记录是近年来光盘存储技术发展的主要方向,存储密度每平方英寸可达20－250G。这篇论文介绍了近场光记录技术（NFOD）的几个关键技术问题,并揭示了NFOD光学头中带缺陷的超微锥尖量子阱激光器的电光波导过程。它首次提出了超微量子阱激光器的三级近似的模型并对其中的一、二级近似进行了仿真计算,计算结果给出了激光器的输入电流与输出光场之间的关系、近场输出光强的分布曲线,这对于NFOD超微光学头的设计是非常重要的。     

超分辨率近场结构(Super-RENS)光存储技术研究进展

传统的光盘系统(如CD、DVD),以及当前的蓝 光系统(如Blu-Ray、HD-DVD)都是一种远场二维存 储技术,能分辨的最小记录符的大小受到光学衍射极限 的限制,存储密度已接近了物理极限。通过总结国内外 近10年的光存储技术的研究不难发现,光存储技术正悄     

基于HLA的空间光学探测仿真系统设计

为支持星载光学相机的设计论证以及更好的发挥其在空间探测领域的应用需求,设计了一种基于HLA的分布式空间光学探测仿真体系.在对仿真任务进行分析的基础上,进行仿真系统各模型的建模,并以组件重用性和系统可扩展性为目标,运用HLA分布式技术设计了系统的体系结构,最终实现了整个联邦的开发.该系统能够为不同类型的光学载荷、不同轨道姿态控制方式的卫星平台、不同类型目标及背景环境等提供仿真服务.最后,以探测目标卫星为例,表明了该仿真平台的可行性,为进一步研究星载光学相机以及其在空间探测领域的应用提供了良好的仿真支撑环境.     

我国光存储技术基础研究的进展(续)

三、超分辨率存储在光学领域中,凡是能使分辨率高于光学衍射极限的技术被通称超分辨率技术,其主要机理在于两个方面:通过对光学系统进行改进实现超分辨率,或者采用新的存储介质结构来实现超分辨率。超分辨率技术应用在光存储领域,可以有效提高存储密度,增大存储容量。近来,在光存储领域中得到应用的主要有近场存储技术和超分辨率光盘。近场存储在光学超分辨率技术中,能显著提高分辨率方法就     

Comparison of image reconstruction by using near‐field and far‐field data for an imperfect conductor

Image reconstruction by using near‐field and far‐field data for an imperfectly conducting cylinder is investigated. A conducting cylinder of unknown shape and conductivity scatters the incident wave in free space and the scattered near and far fields are measured. By using measured fields, the imaging problem is reformulated into an optimization problem and solved by the genetic algorithm. Numerical results show that the convergence speed and final reconstructed results by using near‐field data are better than those obtained by using far‐field data. This work provides both comparative and quantitative information. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 69–73, 2001.     

Exit pupil expander with a large field of view based on diffractive optics

Abstract— The field of view is an important parameter of a near‐to‐eye display. To achieve an immersive viewing experience, the field of view should be as high as possible. Presently, in most of the commercially available devices the field of view is between 15° and 30°. In this paper, a large‐field‐of‐view exit pupil expander that is based on diffractive optics was demonstrated. Usually these types of diffractive expanders cannot have a field of view much more than 25°. Here, an exit pupil expander with an extended field of view, based on two stacked plates, was demonstrated. The expander is designed for green light and it achieves a field of view of more than 40°.     

Design of near-field recording optics using truncated hemispherical SIL with cover-layer incident dual recording layers

In this paper, we propose a novel optics design for media inside near-field recording (NFR) using a truncated hemispherical solid immersion lens (HMS). To obtain strong advantage of data protection and high data capacity simultaneously, a truncated HMS based near field optics with cover-layer incident dual recording layers is designed. In this design, to improve the small optical tolerance of the truncated HMS unit and to adjust dual focusing positions, an additional aspheric lens surface is added on top of the truncated HMS and it is combined with zoom optics composed of two single lenses having a low numerical aperture (NA). Also, to compensate for chromatic aberration, which is a serious problem for optics using a blue laser diode, a diffractive optical element is also designed. Using zoom optics, an additional aspheric lens surface, and a diffractive optical element together, the wavefront aberration and chromatic aberration are effectively reduced in a broad range of cover-layer thicknesses and wavelength variations. In addition, in this paper, the effect of a gap induced aberration is investigated by analyzing the different behavior of each TM and TE wave for the cover-layer incident NFR optics.Paper presented at the 15th Annual Symposium on Information Storage and Processing Systems, Santa Clara, CA, USA, 28–29 June, 2005.     

Diffractive optics for virtual reality displays

Abstract— Near‐to‐eye (NTE) displays are generally systems where the imaging optics of a microdisplay is brought close to the eye, like a magnifying glass. In portable NTE terminals, the challenges are in achieving low power consumption as well as low weight and small size. Part of the problem is related to the microdisplay, but the optics also plays a major role. A study on how diffractive optical elements (DOEs) on planar waveguides can be used to miniaturize the optics of NTE displays is presented and the performance of the system is analyzed.     

A decoupled source current reconstruction method for noisy and reactive near‐field to far‐field transformation

In this article, a decoupled source current reconstruction method (SRM) for noisy and reactive near‐field (NF) to far‐field (FF) transformation is introduced. It is shown that the traditional SRM for NF/FF transformation shows instability in the regions that the amounts of noise or reactive radiations are noticeable. Therefore, in these regions, equivalent currents should be determined from a Tikhonov SRM equation. However, this equation increases the computational cost of the SRM. To simplify the Tikhonov SRM equation, a Tikhonov radial field retrieval algorithm is also proposed. In this algorithm, the Tikhonov integral equation is decoupled by considering and retrieving the radial components of the electric field. Results of far‐field calculation with both the proposed Tikhonov SRM equation and Tikhonov radial field retrieval algorithm with three different antennas are presented and compared with those of the full‐wave simulation and measurements. The results show more accurate field transformation with the proposed algorithms.     

量子光学优化算法*

通过分析光学优化算法的特性,将光学优化算法中每个光源点都用量子空间中的一个粒子来描述,利用群体智慧的聚集性,建立了光学优化算法的量子势能场模型,并根据势能场模型的群体自组织性和协同性等特点提出了量子光学优化算法。通过对多个经典测试函仿真分析,得出量子光学优化算法在量子力学收敛理论下比光学优化算法控制参数少,设置简单,优化性能更好,收敛速度更快,优化了算法的收敛精度和速度。     

On some prerequisites of correlation singular optics as a branch of information optics

Singular optics is the important and dynamically developed area of modern photonics merging with nono-physics, metamaterials, biomedical optics and having promising applications in metrology, interferometry, manipulation of minute quantities of a matter, as well as in information optics, including optical computing and telecommunications. Since the beginning of the Third Millenium, singular optics trends toward expansing on partially coherent, heterogeneously polarized and polychromatic light fields. We consider here some early forerunners of this trend showing that important prereqisities of correlation singular optics lie in the fundamentals of classical optics, such as the notions of diffraction, partial coherence and partial polarization, that put in evidence logicality and prospects of this field of research.     

光场显著性检测研究综述

显著性检测一直是计算机视觉领域的关键问题,在视觉跟踪、图像压缩和目标识别等方面有着非常重要的应用。基于传统RGB图像和RGB-D （RGB depth）图像的显著性检测易受复杂背景、光照、遮挡等因素影响,在复杂场景的检测精度较低,鲁棒的显著性检测仍存在很大挑战。随着光场成像技术的发展,人们开始从新的途径解决显著性检测问题。光场数据记录着空间光线位置信息和方向信息,隐含场景的几何结构,能为显著性检测提供可靠的背景、深度等先验信息。因此,利用光场数据进行显著性检测得到了广泛关注,成为研究热点。尽管基于光场数据的显著性检测算法陆续出现,但是缺少对该问题的深刻理解以及研究进展的全面综述。本文系统地综述了基于光场数据的显著性检测研究现状,并进行深入探讨和展望。对光场理论以及用于光场显著性检测的公共数据集进行介绍;系统地介绍了光场显著性检测领域的算法模型和最新进展,从人工设计光场特征、稀疏编码特征和深度学习特征等方面进行全面阐述及分析;通过4个公共光场显著性数据集上的实验数据对不同方法的优缺点进行比较和分析,并结合实际应用指出当前研究的局限性与发展趋势。     

闭环光纤陀螺信号检测与处理方法

介绍了干涉型光纤陀螺的基本原理 ,提出了一种基于多功能集成光学器件Y波导和现场可编程门阵列的全数字化信号检测与处理方案。采用了该方案的样机实测的零漂移低于 0 .5 3°/h ,证实了方案的可行性。     

Harvesting light with transformation optics

Transformation optics （TO） is a new tool for controlling electromagnetic fields. In the context of metamaterial technology, it provides a direct link between a desired electromagnetic （EM） phenomenon and the material response required for its occurrence. Recently, this powerful framework has been successfully exploited to study surface plasmon assisted phenomena such as light harvesting. Here, we review the general strategy based on TO to design plasmonic devices capable of harvesting light over a broadband spectrum and achieving considerable field confinement and enhancement. The methodology starts with two-dimensional （2D） cases, such as 2D metal edges, crescent-shaped cylinders, nanowire dimers, and rough metal surfaces, and is well extended to fully-fledged three-dimensional （3D） situations. The largely analytic approach gives physical insights into the processes involved and suggests a way forward to study a wide variety of plasmonic nanostructures.