光学元件面形的环路径向剪切干涉检测方法研究

提出了将环路径向剪切干涉(CRSI,Cyclic Radial Shearing Interferometry)术应用于光学元件面形检测的新方法.设计了基于环路径向剪切干涉检测光学元件面形的光路系统.根据环路径向剪切干涉法的波前重建算法,模拟计算了任意波前的重建情况,同时在基于开普勒望远系统的环路径向剪切干涉仪上实际测量了一个已知光学元件的面形.结果表明,文中提出的波前重建算法和采用的光路系统可用于实际光学元件面形的准确检测,系统的重复性也得到了研究.     

利用液晶电视的位相调制特性补偿畸变波前

分析了液晶电视(LCTV)的位相调制特性,采用将液晶电视和能产生台阶波前畸变的位相物体同时置于环路径向剪切干涉(CRSI)装置入射光路中的方法,在液晶电视屏上输入可产生畸变波前对应的互补波前的灰度图。实现了台阶结构畸变波前的补偿。     

径向剪切干涉测量激光光束波前的研究

详细论述了环路径向剪切干涉（cyclic raial shearing interferometry,CRSI）测量激光光束波前的原理,介绍了傅立叶变换空间载波条纹相位提取方法,以及畸变波前的重建算法,给出了数值仿真结果,并且进行了实验研究,验证了该方法的有效性.     

基于时域剪切的纳秒脉冲在线测量算法

为了从单幅时域剪切干涉图中重建出纳秒激光脉冲的振幅分布,提出了一种基于自参考时域剪切的纳秒脉冲在线测量算法。首先,在对振幅重建原理进行系统分析的基础上,通过数值模拟验证了该振幅重建算法的可行性。然后,给出了实验中各参数的选取原则,并通过实验验证该振幅重建算法的可行性。实验结果表明,该算法不需要额外增加测量光路就能实现脉冲时间强度分布的重建,具有测量原理简单、适用范围广等特点,为纳秒激光脉冲全域特性的测量提供了一种新思路。     

径向剪切干涉波面重构的数值模拟分析

径向剪切干涉仪所采集到的干涉图并不直接反映原始待测波面信息,为了获得原始待测波面信息,波面重构是必要的。推导了波面重构的迭代算法,并用Matlab分别对径向剪切中不同迭代次数、不同剪切比的波面重构迭代算法进行了数值模拟,得出以下结论:合适的剪切比可以简化迭代运算,提高运算速度;与小畸变波面重构相比,残差波面PV值达到相同精度时,大畸变波面重构需要更多的迭代次数。待测波面的PV值大于10时,剪切比应在0.7以上,PV值大于6小于10,剪切比在0.5~0.7之间,PV值小于6,剪切比小于0.5。     

减小正弦相位调制菲佐干涉仪多光束干涉影响的方法

在利用正弦相位调制菲佐干涉仪进行测量时,由于菲佐板及待测物体表面对入射光的多次反射而产生多光束干涉,干涉信号的强度随相位变化不是严格的余弦分布.按照双光束干涉的算法进行相位信息提取,会引入一定的误差.以正弦相位凋制菲佐干涉仪纳米精度微小位移测量为应用背景,分析多光束干涉情况下该干涉仪信号解调算法的误差,进而对干涉仪的相关参数进行优化,并通过误差补偿对测量结果进行修正,有效减小了多光束干涉产生的影响.     

锥形表面反射波前干涉术

在高能激光器设计中,提出采用新的先进的光学元件。具有典型代表的元件有锥面、反射式轴向镜(refaxicon)和W形锥镜(waxicon)。这些光学元件不属空间不变(等晕)光学系统,因为径向曲率半径以及径向的光学能量随入射到光学表面的光线高度而变化。这些光学元件的非线性特性不可能用典型的线性等晕光学系统理论来论述。这些元件的非线性特性要求对干涉术进行待殊的考虑。通常用三种干涉仪作表面干涉测量仪,即合曼—格林干涉仪、剪切干涉仪和斐索干涉仪。除剪切干涉仪外,所有的干涉仪都要求高质量输入波前和高质量参考表面,用多次曝光干涉图和三个近于相同的参考面.表面测量量可能达到的精度约为λ/100。     

用于高重复频率热容主振荡功率放大器激光系统的波前检测技术

高重复频率热容主振荡功率放大器(MOPA)激光系统的工作过程一般只持续几秒至几十秒,在此过程中系统输出光束的波前畸变是动态变化的。采用环路径向剪切干涉(CRWSI)技术对高重复频率热容MOPA系统波前畸变的变化过程进行检测,并对系统的总体结构进行了设计。搭建了一个简化的实验系统,采用平凹透镜来代替光放大器产生波前畸变,并由此对环路径向剪切干涉仪的测量精度进行了验证。结果表明,实验测量结果与理论计算值之间的峰值误差为7.8%(0.02λ)。     

基于马赫-曾德尔点衍射干涉仪的激光模式复振幅测量

利用马赫-曾德尔点衍射干涉仪,通过一幅干涉图,直接恢复激光模式的强度和相位信息,重建模式复振幅。在理论上分析了利用快速傅里叶变换的点衍射干涉法重建激光复振幅分布的原理;推导了激光模式在自由空间中传输时强度和相位的分布情况。将模拟的分布与实验结果做了比较,结果表明,点衍射干涉法可以恢复激光模式的强度和相位信息。     

空间外差光谱仪干涉图修正研究

空间外差光谱技术（Spatial heterodyne spectroscopy, SHS）是一种新型的光谱分析技术,本文基于空间外差光谱仪的基本原理和特点,研究了实际测量中干涉仪两光臂不平衡造成的畸变干涉图的修正方法,模拟计算了干涉仪两光臂不平衡时干涉图的强度变化,并对其进行了模拟修正,修正后的干涉图与理想的SHS干涉图一致性较好。修正方法主要是测量干涉图的非调制项（即未发生干涉时单个光臂的光强）,以及在干涉图数据处理中引入了一个修正因子。通过对干涉仪两臂不平衡的修正,可以有效地提高干涉图反演光谱的精度。     

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.     

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.     

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.     

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.     

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 rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks