一种离轴抛物面准直光管的设计

论述了一种用于为某可靠性测试设备提供红外模拟目标源的离轴抛物面准直光管系统的结构选择.按照焦距f=960mm,相对孔径1:6,视场0.6°,工作谱段0.8～1.4μm的技术要求,对准直光管的光学系统进行了设计.反射式光学系统,能做到大口径和无色差及轻量化设计,系统光利用率高.因系统要求中心无遮拦,故选用离轴抛物面式准直系统.为进一步改善系统像质,采用了离轴高次抛物面式主反射镜与次反射镜以及补偿透镜组的设计方案.模拟实验表明,此准直光管的主要性能满足使用要求.     

大视场离轴三反光学系统设计

与传统折射光学系统相比,离轴反射光学系统具有小体积、轻量化和无色差等特点,因此被广泛应用于望远镜系统和空间观测系统等领域。随着目前自由曲面的广泛应用,首先分析了离轴三反光学系统的初始结构参数确定方法,然后在系统的主反射镜设计中引入Zernike边缘矢高形式的自由曲面,最终设计了一款有效焦距为700 mm,视场角为10°,F/#为4.5,系统总长为597.58 mm的离轴三反光学系统。该系统在71.4 lp/mm处各视场的调制传递函数(MTF)值均大于0.28,畸变均小于0.1%,结果表明,该系统在有效视场内成像质量较好。该系统的设计方法对类似的离轴三反光学系统设计具有一定的参考价值。     

离轴四反射镜光学系统设计

与一般光学系统相比,航空遥感光学系统具有长焦距、大口径、宽波段等特点。因此,广泛使用反射式光学系统。常见的离轴三反系统已不能满足系统小型化、轻量化的要求。介绍了一种无中心遮拦的离轴四反射镜系统,由离轴三反系统改进而成,结构更加紧凑。带一次中间像面的离轴三反系统的中间像位于次镜和三镜之间,为了进一步折叠光路,在中间像面处加入球面反射场镜,从而成为离轴四反。分析了离轴四反的设计步骤,设计了一个焦距为1 200 mm,视场为0.8°×0.8°,相对孔径为F/6的光学系统,系统总长只有300 mm,并达到很好的光学性能,具有长焦距、小尺寸、良好的杂散光抑制能力等特点。     

一种含自由曲面的离轴三反光学系统设计

设计了一种含自由曲面的离轴三反射镜红外光学系统,光学系统采用三个离轴反射镜,其中第二反射镜采用自由曲面面型,其余反射镜采用非球面面型。光学系统接收口径Φ100mm,F/#25。由于反射元件不产生色差,因此光学系统不存在色差。同时反射元件与支撑结构件采用同一材料,光学系统实现无热化设计。利用自由曲面的非旋转对称性,系统轴外像差得到了很好的校正,从而使光学系统成像质量接近衍射极限。通过合理布局三个反射镜的位置,使光学系统外形尺寸达到了160mm×110mm×250mm。     

自由曲面在离轴光学系统中的应用

针对自由曲面能提升成像光学系统的性能和校正像差的特点,分析了自由曲面在离轴光学系统中的应用优势。光学系统选用视场角为30°×11°、焦距为150 mm、F数为3的Cook-TMA。本设计中,离轴三反光学系统的主反射镜采用自由曲面设计。分析了使用Zernike多项式曲面在大视场离轴反射式光学系统中对离轴光学系统性能的提升效果,并与使用常规非球面的情况进行了比较,分析了自由曲面的优缺点。结果表明,自由曲面在提高离轴光学系统的成像质量方面具有更大的优势,系统的平均传递函数比常规非球面提升了15.9%以上,系统接近衍射极限。Zernike多项式曲面在离轴三反系统中的应用效果良好,系统的成像性能得到了较大的提升。     

紧凑型四反射镜光学系统设计

离轴四反射镜较之于TMA系统,可更好地满足无人侦察机对于光学系统小型化、轻量化的需求。给出了一种基于赛德尔像差理论的四反射镜光学系统的设计方法。依据该方法,设计了一个焦距1000 mm,视场1.6°,相对孔径为F/5的光学系统。系统结构紧凑,成像质量接近衍射极限,具有长焦距和良好的杂散光抑制能力,体现了四反射镜系统的优势,证明了该理论的可行性与实用性。     

自由曲面离轴四反全铝光机红外探测系统(特邀)EI北大核心CSCD

为满足红外探测系统对大视场、轻量化、低成本的需求,设计并研制了一款用于制冷型红外探测器的自由曲面离轴四反全铝光机系统。光学设计采用具有实出瞳的离轴无遮拦全反射式光路形式,并利用7次XY多项式表征各反射镜面型。在紧凑包络约束下,实现了6.25°×5°的视场角,全视场RMS几何弥散斑半径<6.0μm。各反射镜和支撑结构材料均选用6061-T651铝合金,各反射镜进行了柔性支撑设计,以降低装调时的刚性连接应力。采用激光干涉仪对光机系统波像差进行了测试,典型视场波像差相似文献   

自由曲面在制冷型离轴三反光学系统的应用

研究了制冷型红外离轴三反光学系统成像原理和优化设计方法。给出了一个应用自由曲面的制冷型离轴三反射镜光学系统的设计。系统采用两个自由曲面反射镜和一个偶次非球面反射镜组成二次成像的结构形式,将制冷型红外探测器的冷光阑作为系统的孔径光阑,得到100%的冷光阑效率。第二和第三反射镜将孔径光阑成像在第一反射镜的位置,显著减小第一反射镜的口径。通过调整每个反射镜的偏心与倾斜,实现系统的无遮拦,使用自由曲面增大视场、校正像差、保证系统的成像质量。该系统的工作波段为3~5 m,焦距为450 mm,F数为2,视场为3.6622.931,各视场的调制传递函数在环境温度为-40~60℃的范围内均高于0.5,实现系统的无热化,并且结构紧凑。     

可见光与红外光轴平行度检测仪

将可见光与红外光学系统运用分光镜和卡塞格伦平行光学系统组合成平行共光路系统.运用这一特性研发了红外与可见光发射光轴平行度检测仪,用红外和可见光CCD作为传感器.在平行度检测仪前放置标准平面反射镜,进行自准标校.进行平行度检测时,检测仪放置在被测复合光学系统前,标准平面反射镜放置在光学系统后.调整平行度检测仪,使检测仪的可见光轴与复合光学系统的可见光轴平行;再调标准平面反射镜,使可见光学系统成自准直像.以可见光轴为基准,采集检测仪经复合光学系统及标准平面反射镜后的红外像.进行图像分析及数据处理,得到复合光学系统红外光轴与可见光轴的平行度.检测仪的不确定度为3.5".     

一种改进的易于加工、装调的离轴三反光学系统设计

为了降低离轴三反光学系统加工和装调难度,提出了一种无遮拦的两反射镜三反射光学系统。将传统的离轴三反射光学系统中的主镜和三镜改进为一块非球面反射镜,即用一块镜面实现两镜的设计,这既能够降低光学加工的复杂度,同时也减少了装调的难度。根据三反射系统像差设计理论,推导出同轴两反射镜三反射系统的初始结构参数计算公式,得出了适用于该系统的求解方程组。设计了焦距1000 mm,F数为10,全视场2°×0.4°,无中心遮拦的离轴两镜三反射系统,两反射镜面型均为二次曲面。从调制传递函数、点列图、衍射能量分布图可以看出,系统成像质量好,能量比较集中。整体系统体积小、结构简单,重量轻。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.