共查询到20条相似文献,搜索用时 62 毫秒
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为提高光学相干层析术(OCT)系统成像速度,借助成像光谱仪,以钨灯为非相干光源,采用柱面镜聚焦,搭建了迈克耳孙干涉仪结构的无扫描装置谱域OCT系统。介绍了系统结构和工作原理,对待测样品进行了层析成像实验,分析了系统的成像特性,利用中值滤波的方法消除背景噪声,获得了样品的二维层析图像,与点扫描光纤型OCT的成像速度进行了比较。研究表明,无扫描装置谱域OCT系统在8mm宽度范围成像时,其数据采集速度比传统点扫描方式约快2个数量级。 相似文献
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偏振光学成像是一种非标记、无损伤的检测技术,对亚波长微观结构的变化比较敏感,可以提供丰富的组织结构和光学信息。然而,在可见波段范围内,生物组织是强散射介质,光在组织中传播时会经历多次散射,失去原本携带的相位和偏振信息,从而影响光学成像的对比度和分辨率。本团队结合空间频域成像和偏振光学成像方法,搭建了偏振空间频域成像系统。通过高频空间频域成像控制照明光的穿透深度,利用穆勒矩阵表征样品浅层的偏振参数,进而反映样品浅层的微观结构信息。实验结果显示:偏振空间频域成像系统测得的灰阶板漫反射率与标准值线性相关(R2=0.99988);退偏系数与脂肪乳体积分数成正比关系,二向衰减系数随二向衰减器导致的二向衰减增大而增大;该系统可以准确测量四分之一波片和全波片的相位延迟,表明该系统可以准确测量样品的偏振参数。对比传统偏振光成像和偏振空间频域成像结果可以发现,偏振空间频域成像可以有效控制成像深度,精确测量样品浅层的穆勒矩阵。采用该系统对烧伤猪皮进行检测,测量结果显示:猪皮组织内部的胶原蛋白结构被破坏,相位延迟降低。本研究结果预期能够有效提升浅层组织偏振特性检测的准确性,促进肿瘤的早... 相似文献
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光学相干层析成像(OCT)能够无损获得微米级空间分辨率的样品截面信息,在眼科、血管内科等临床诊疗研究和应用中起到了重要的作用。利用OCT测量光场的幅度可以获得样本的三维结构信息,如眼底视网膜的分层结构,但对组织特异性、血流、力学特性等功能信息的作用有限。基于相位、偏振态、波长等光场参量的OCT功能成像技术应运而生,如多普勒OCT、OCT弹性成像、偏振敏感OCT、可见光OCT等。其中,基于光场幅度动态变化的OCT功能成像技术具有显著的鲁棒性和系统复杂度优势,已经在临床无标记血管造影中获得成功。此外,应用于三维血流流速测量的动态光散射OCT、具有无标记组织/细胞特异性显示能力的动态OCT、能够监控热物理治疗温度场的OCT温度层析成像等,已经成为了OCT功能成像的技术前沿。综述基于光场幅度动态变化的OCT功能成像技术的原理、实现和应用,分析了所面临的技术挑战,并展望了未来发展方向。 相似文献
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增大频域光学相干层析术(FDOCT)成像深度是扩大FDOCT应用范围的一个关键。主要研究了基于像素平移法提高频域OCT成像深度的问题。讨论了像素平移法的基本原理,阐述了频域OCT理论最大成像深度与电荷耦合元件(CCD)像素数的关系。通过点扩散函数实验、5层盖玻片成像实验以及手指皮肤的活体成像实验验证了像素平移法对于提高频域OCT成像深度的作用。手指皮肤的成像实验表明256个像素点的CCD和512个像素点的CCD采用像素平移法后实际成像深度分别增加到了原来的1.98倍和1.12倍。Matlab软件模拟验证方法为频域OCT系统中CCD的像素数选择提供了参考。 相似文献
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1300nm光学层析成像 总被引:4,自引:2,他引:2
利用光学相干层析(OCT)技术,可以透过混沌介质,特别是生物组织成像。本文介绍了我们建立的基于1300nm波长稳定化光源的OCT实验装置,并且该装置测量了金属丝样品在奶粉溶液和土豆片两种混沌介质的一维和二维成像情况。该装置具有20μm的横向分辨率和26μm的轴向分辨率,并给出由OCT信号重建的灰度图。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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. 相似文献
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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. 相似文献
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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. 相似文献
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《中国通信》2014,(7)
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 相似文献
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《中国通信》2014,(8)
正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first 相似文献