光源附近组织的空间分辨漫反射研究

P3 近似理论可以描述光源附近约1个输运平均自由程(MFP)内组织的漫反射光分布,这个区域的光分布与组织的散射相函数有关。利用P3 近似理论研究了组合相函数的结构因子α对光源附近组织的漫反射光分布的影响。研究表明:在输运平均自由程不变条件下,各向异性因子的变化不引起漫射近似适用区域光分布的改变,但对光源附近约1个输运平均自由程附近的光分布有很大影响;α对漫反射率的影响远大于相函数的高阶矩对漫反射率的影响。研究结果对于使用内窥方式或对表层组织进行活体检测的空间分辨漫反射测量技术具有实际意义。     

光源附近组织的空问分辨漫反射研究

P3近似理论可以描述光源附近约1个输运平均自由程(MFP)内组织的漫反射光分布，这个区域的光分布与组织的散射相函数有关。利用P3近似理论研究了组合相函数的结构因子α对光源附近组织的漫反射光分布的影响。研究表明：在输运平均自由程不变条件下，各向异性因子的变化不引起漫射近似适用区域光分布的改变，但对光源附近约1个输运平均自由程附近的光分布有很大影响；α对漫反射率的影响远大于相函数的高阶矩对漫反射率的影响。研究结果对于使用内窥方式或对表层组织进行活体检测的空间分辨漫反射测量技术具有实际意义。     

基于LS-SVM测量生物组织光学参量的实验研究

为了实现无损测量生物组织光学参量,利用CCD技术结合最小二乘支持向量机,对测量组织模拟液的光学参量进行了实验研究。通过实验测量了组织模拟液的表面漫反射光分布,建立了漫反射光分布与光学参量间的最小二乘支持向量机回归模型,该模型实现了小样本条件下对组织模拟液光学参量的预测误差仅为5%。结果表明,最小二乘支持向量机结合CCD测量技术能够准确测量组织模拟液的光学参量。     

标准激光光源近场空域测量精度研究

为了研究标准激光光源近场空域测量精度,在理论方面建立了标准激光光源近场强度分布的理论模型,在实验方面提出了科学级CCD面响应非均匀性校正方案和激光近场计算算法。利用非均匀性校正后的科学级CCD和二维扫描装置,在1053nm标准激光光源软边光阑50mm×50mm口径内S形扫描,通过子孔径拼接得到标准激光光源近场图像。近场分布测试结果与理论值一致,差异主要是因为离轴抛物面镜表面粗糙度与科学级CCD随机噪声产生了高频分量。对近场参数测试结果进行分析,调制度扩展不确定度为0.08(k=2),对比度扩展不确定度为0.01(k=2)。研究结果提高了国家大科学工程激光参数测量系统近场空域测试置信度。     

基于谐波检测原理的双光路CH4检测研究

基于谐波检测原理,研究了一种高灵敏度易于实现的近红外光谱吸收型光纤CH4气体传感器.系统采用分布反馈式(DFB)LD做光源,通过光源调制实现气体浓度的谐波检测,加入参考光路和参考气室,利用2个二次谐波的比值作为系统输出,消除了光源波动和光路干扰的影响,建立了传感器的数学模型,给出了CH4气体测量系统的实验结果,实验表明,该仪器的检测灵敏度可以达到1×10-4.     

基于可视中国人蒙特卡罗分析实现肺部无创光学监测的探讨

肺部疾病的诊断和治疗很重要，目前实现肺部疾病的无创监测具有一定困难。笔者采用近红外光子传输技术，定量研究了人体肺部的结构。以可视中国人数据集（VCH）为实验对象，利用蒙特卡罗（MC）模拟对其进行了仿真。对肺部血流动力学非侵入式测量的可行性进行了理论探讨，并对光子在肺部传输时的最佳光源位置进行了研究，同时还对光源-检测器距离进行了优化。光通量强度显示，光子在人体肺部可以穿透6～8.4 mm，光源到检测器的最佳距离是2.8～3.6 cm。在此基础上，对13名志愿者进行了近红外漫反射实验，实验数据与仿真结果基本一致。实验结果表明，本研究在肺部血流动力学无创监测方面具有广阔的应用前景，同时也为生物医学光学技术在人体上的应用提供了参考。     

微细管道内壁缺陷测量系统构建和技术

为满足微细管道内部缺陷检测需要,提出了一种将外部光源导入、内部图像导出的解决新思路,基于360°全景锥镜、视像管、环形光源、近景光学镜头及高分辨率相机构建了光学信息传输部件,并与计算机共同组成机器视觉检测系统。在检测系统构建中,光学信息传输部件的姿态调整是一个关键环节,本文对此展开了深入的研究,给出了调整评判依据及完整的调整实现流程,最终构建了较为理想的微细管道内部缺陷测量系统。基于测量系统,对深100mm、孔径9mm的管道样件内壁上0.5、0.8及1.0mm的微孔模拟缺陷进行了多次测量,测量结果标准差分别为0.025、0.026及0.028mm。实验结果表明,基于本文的调整技术构建的检测系统,可以实现检测部件与待测管道的精确对准,进而实现微细管道内部缺陷的高精度测量。     

光源闪烁对眩光评价的影响

本文分析了眩光测量过程中,光源闪烁对眩光测量结果的影响.针对光源部分的测量,分别采用了高动态模式和闪烁光源分析模式分析了在不同曝光时间对眩光测量结果标准偏差和重复性的影响.当曝光时间远小于光源的闪烁周期时,虽然可以避免眩光亮度计过曝对光源亮度测量结果的影响.但是眩光测量结果的重复性较差,无法给出准确的眩光测量结果.而当曝光时间大于光源闪烁周期时,测量结果的偏差和重复性有着极大的提高.当曝光时间达到光源闪烁周期的10倍时,可以避免光源闪烁对眩光测量结果的影响.     

离散介质表面漫反射光的空间分布特性

采用Monte Carlo方法和实验,对离散介质表面漫反射光的空间分布进行了研究.结果表明：离散介质表面并非理想朗伯表面;用置换法对整个生物组织漫反射率的平切光纤测量系统进行简单的定标中,把生物组织表面作为朗伯表面处理将使漫反射率计算结果存在偏差,准确的做法应是对漫反射进行空间积分.     

生物组织光学特性参量的图像测量研究

为了测量生物组织的光学特性参量,采用CCD漫反射法和透射法,通过分析CCD摄取的待测样品表面的漫反射光分布图像,利用漫射近似理论,实现了漫反射法对生物组织模拟液(intralipid-20%稀释液)、牛肌肉、猪肌肉和鸡胸肉光学特性参量的测量,获得了样品的吸收系数和有效散射系数;测量了不同浓度生物组织模拟液的透射光强度,根据Beer-Lambert定律,实现了透射法对光学特性参量的测量,获得了样品的散射系数,进而得到了有效散射系数;并将漫反射法和透射法对同种样品光学特性参量的测量结果以及他人的测量结果进行了比较。结果表明,漫反射法和透射法的测量结果有很好的吻合性,测量生物组织光学特性参量采用的CCD测量装置和处理方法具有较高的精度。     

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.     

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.