共查询到20条相似文献,搜索用时 78 毫秒
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为了增强相对论飞秒激光与固体靶相互作用下太赫兹波的产生,提出了前端锥形开口的纳米丝靶结构,并通过胞中粒子法(Particle-In-Cell)数值模拟,研究了该结构对太赫兹波产生的影响,还与普通结构的纳米丝靶所产生的太赫兹波结果进行了对比。结果显示,前端锥形开口的纳米丝靶结构能够明显增强太赫兹波的产生,在探测点位置得到了比普通纳米丝靶中的太赫兹波电场强3倍的结果。最后详细分析了不同靶型结构影响太赫兹波产生的物理因素,发现不同靶型结构通过影响入射激光的吸收与反射,进而影响靶后超热电子的能量与数目。上述研究结果将有助于推动强场太赫兹波领域的发展,为实验研究提供方案和数据支撑。 相似文献
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太赫兹波成像技术在生物医疗和安全检测等领域具有广阔的应用前景。针对新一代信息技术对便携式太赫兹波成像设备的需求,设计了基于CMOS太赫兹波探测器的成像系统。该系统包括一款CMOS太赫兹波探测器、片外模数转换器(ADC)、FPGA数字信号处理器、二位步进机、四个抛物面镜和太赫兹波辐射源等。CMOS太赫兹波探测器集成了片上贴片天线以及作为检波元件的NMOS晶体管,探测器由180 nm标准CMOS工艺制成。太赫兹波探测器的输出被片外模数转换器(ADC)采集并转换为数字信号,该数字信号被FPGA采集并传输到电脑上成像。所有上述元件均被装备在印刷线路板(PCB)上以减小系统体积。该系统实现了透射式太赫兹波扫描成像而无需斩波-锁相技术,并给出在860 GHz的太赫兹波照射下隐藏在信封内部金属的成像结果。 相似文献
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研究了焦点位置附近太赫兹波的横模分布,目的在于了解系统中太赫兹波的横向分布情况,为进行太赫兹光谱和成像实验提供依据。通过太赫兹波逐点扫描成像,对经常被用来放置测试样品位置附近的太赫兹波横模分布情况进行了定性的分析。利用“狭缝法"测量了太赫兹光束的束宽。结果表明,太赫兹波在焦点附近不同位置的横向分布有较大差异,在焦点处对应于最长波长1.5 mm的最小光斑直径约为1.0 mm,这说明太赫兹波的聚焦有一定的限度。实验确定了系统中放置样品的最佳位置,对开展太赫兹光谱和成像研究有参考价值。 相似文献
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乳腺癌是女性常见癌症之一,乳腺癌区域的精准检测对乳腺癌的治疗有至关重要的作用。本文采用频率为2.52THz的连续太赫兹波反射式成像系统,对小鼠在体皮下乳腺癌模型进行了太赫兹波成像检测。研究结果表明,太赫兹波成像可以清晰识别出乳腺癌区域,且与肉眼可见肿瘤区域一致。在体乳腺癌区域的太赫兹波相对反射率高于正常组织,两者相对反射率差值高达15%。进一步,对距离皮肤表面不同深度的离体乳腺癌组织进行切片和苏木精-伊红(H&E)染色,作为金标准对照。结果发现乳腺癌区域的面积随着距离皮肤表面深度的增加而增大。通过将太赫兹波成像与H&E染色结果对比可知,在距离皮肤表面约460μm处,太赫兹波图像和H&E染色图中的肿瘤区域面积相等。由此可知,太赫兹波对在体皮下乳腺癌的探测深度大约在460μm左右,太赫兹波有望实现深部肿瘤的检测。 相似文献
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主要探讨自然界树叶样本的太赫兹透射成像中的对比度与透射频率的关系。运用透射模式的太赫兹时域光谱系统对样本进行了聚焦逐点式的主动扫描,得到样本各部分的太赫兹波透射率,然后进行数据处理和二维成像。通过对样本在8个不同频率下的太赫兹透射率成像的比对分析,表明样本的不同部分对各个频率的太赫兹波的吸收都有较明显的差别。为了得到更清晰的太赫兹成像,必须选取合适的成像频率使样本成像的对比度更佳,实验发现应该选择透射振幅适中的频段,且在此范围内样品的某些部分具有吸收峰的频率附近进行成像。 相似文献
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太赫兹技术及其应用研究的进展 总被引:5,自引:1,他引:4
过去十年来,太赫兹技术理论研究的蓬勃发展带动了太赫兹波应用领域的迅速扩大。本文概述了太赫兹波的产生、探测技术等基础研究的现状,重点介绍了近年来太赫兹波在物体成像、环境监测、军事和通信、医学和生物及其它几个应用领域的研究进展和最新研究成果。 相似文献
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太赫兹波在军事领域中的应用研究 总被引:6,自引:2,他引:4
详细介绍了太赫兹波的优良性质及利用光导天线和光整流产生太赫兹波的方法.从远程监视、成像、爆炸物鉴别及无损检测等方面,重点介绍了太赫兹技术在军事领域中的应用. 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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GU Min-fen LIANG Zhong-cheng WANG Ren-zhou DONG Xiang-mei ZHANG Pei-ming CHEN Jia-bi 《光电子快报》2008,4(2):150-152
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. 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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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. 相似文献
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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. 相似文献
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An insert layer structure organic electroluminescent device(OLED) based on a new luminescent material (Zn(salen)) is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn(salen)/Liq/LiF/A1/CuPc/NPD/Zn(salen)/Liq/LiF/A1. Effective insert electrode layers comprising LiF(1nm)/Al(5 nm) are used as a single semitransparent mirror, and bilayer cathode LiF(1 nm)/A1(100 nm) is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect. 相似文献