共查询到19条相似文献,搜索用时 656 毫秒
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一种探针-样品距离的切变力控制新方法 总被引:1,自引:1,他引:0
报道了近场扫描光学显微镜(Near-filed Scanning Optics Microscope NSOM)中一种基于切变力的探针 样品间距控制新方法.条形压电蜂鸣器片的上表面电极被沿着中心线分成两半,一半用于驱动,其上施加振荡源谐振频率进行激励,另一半上粘附光纤探针,并利用压电效应作为光纤探针的振幅传感器.当受振动激励的光纤探针由远处逐渐接近样品表面时,由于样品与探针之间的切变力阻尼作用使得探针的振幅减小,通过检测探针振幅的变化可以控制探针与样品的间距.我们建立了一套探针 样品间距探测控制系统并利用该系统获得了CD盘片表面8μm×8μm范围内的切变力形貌图. 相似文献
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一种探针-样品距离的切变力控制新方法 总被引:1,自引:1,他引:0
报道了近场扫描光学显微镜(Near-filed Scanning Optics Microscope-NSOM)中一种基于切变力的探针-样品间距控制新方法.条形压电蜂鸣器片的上表面电极被沿着中心线分成两半,一半用于驱动,其上施加振荡源谐振频率进行激励,另一半上粘附光纤探针,并利用压电效应作为光纤探针的振幅传感器.当受振动激励的光纤探针由远处逐渐接近样品表面时,由于样品与探针之间的切变力阻尼作用使得探针的振幅减小,通过检测探针振幅的变化可以控制探针与样品的间距.我们建立了一套探针-样品间距探测控制系统并利用该系统获得了CD盘片表面8μm×8μm范围内的切变力形貌图. 相似文献
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近场光学显微镜中利用剪切力原理进行样品/探针间距测控的非光学方法 总被引:1,自引:0,他引:1
扫描近场光学显微镜(ScanningNear-fieldOpticalMicroscope:SNOM)自80年代中期以来获得了迅速的发展并得到了具有纳米(亚纳米)尺度分辨率的光学图像。作为SNOM的关键技术之一,样品与探针间距的控制尤为重要,而实现起来比较困难。人们提出了多种方法,其中基于剪切力原理的控制方法最常用而且实验证明是可靠的。本文综述了扫描近场光学显微镜发展以来所出现的基于剪切力原理进行样品/探针间距的探测的一些主要的非光学方法。包括利用PMT直接探测样品辐射,利用音叉、电容、阻抗以及压电效应的探没方法等,并对各种方法的优缺点进行了分析比较。 相似文献
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石英音叉作为力传感器广泛地应用于各种扫描探针显微镜,主要涉及石英音叉的同相振动和反相振动两种振动模式.通过实验方法和有限元仿真方法对石英音叉的两种振动模式进行研究,发现石英音叉的双臂之间以及双臂与音叉的基部之间都存在耦合作用,双臂之间的耦合使音叉的反相共振频率升高,双臂与基部之间的耦合使音叉的同相共振频率降低.针对两种振动模式的动态特性建立了石英音叉的机械模型并进行合理简化.简化模型是一个四弹簧三质点系统,计算了简化模型的参数.通过一个音叉臂等效质量变化与音叉反相共振频率变化之间的定量关系证明了简化机械模
关键词:
扫描探针显微镜
石英音叉
振动模式
机械模型 相似文献
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基于叠层衍射成像原理提出了一种新的衍射数字水印算法:叠层水印. 通过双随机相位编码和探针, 实现对水印图像的分块加密, 密文经过衰减处理, 加载在振幅型宿主图像的空域上, 伪探针记录下宿主图像, 并加载到传输图像的相位上. 模拟实验结果表明: 首先, 叠层水印可以很好地提取水印图像的振幅、相位信息. 其次, 叠层水印可以解决水印不可感知性与密文信息提取质量之间的矛盾. 最后, 通过鲁棒性研究验证了: 叠层水印具有很好的抗噪声和抗剪切能力, 并且可以通过增加探针的数目和交叠率进一步提高其鲁棒性, 并给出其在GIF图像上的应用. 相似文献
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近场扫描光学显微术中, 近场距离的检测和控制是需要解决的核心技术之一. 本文研究了基于DDS驱动的压电传感器, 在一个压电陶瓷片上, 电极被分成相同的两部分, 分别用于振动驱动和振幅检测. 近场扫描的光纤探针固定于此压电陶瓷片上. 振动驱动信号采用DDS, 在样品的远场时, 可以通过频率扫描得到误差在0.006 Hz以内的压电陶瓷片谐振频率驱动信号, 而当光纤探针处于样品的近场距离之内时, 压电陶瓷片的谐振频率偏离驱动信号频率, 振幅明显减小, 从而检测出近场距离. 高精度振动驱动源DDS和高灵敏度压电传感器的采用提高了检测灵敏度和工作稳定性. 相似文献
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For the evaluation of two-dimensional carrier profiles in semiconductor devices, we have developed a novel form of probe–sensor combined unit that uses an etched tungsten wire as a conductive probe, and commercially available quartz tuning fork as the force sensor. This unit has a self-sensing capability due to the piezoelectric effect of quartz tuning fork, thus obviating optical setup, and its conductivity is higher and more stable than that of conventional metal-coated Si cantilever. In addition, this probe–sensor combined unit is inexpensive and easy to use, when compared to the well-known optical methods of Si-based cantilever vibration detection system. Our scanning probe microscope using this probe–sensor combined unit is able to mapping the capacitive gradient signal (dC/dZ image) and internal damping of quartz tuning fork oscillation (dissipation image) while scanning the sample surface. In this letter, we show the results of visualization of the p–n junction locus of a Si metal–oxide–semiconductor field effect transistor in both dC/dZ and dissipation images. 相似文献
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The motion of the probe tip in a near-field scanning optical microscope, dithered by vibration of a tuning fork, can modulate the reflection signal from the sample surface not only at the fundamental dithering frequency but also at its second harmonic. By lock-in amplification of these modulated signals, enhanced optical images are obtained, even with an uncoated fiber probe. In particular, accurate optical images with higher resolution are obtained when the second-harmonic signal is detected, which results from the parametric modulation of the tip-sample separation at the double frequency of the horizontal dithering motion of the tip. Using a DVD ROM with a track pitch of 0.74 mum as a test sample, we observed that the sharp edges around the pits are clearly resolved with the second-harmonic signals and obtained enhanced resolution of ~70 nm full width at half-maximum. 相似文献
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Shinya Ohkubo Shohei Yamazaki Atsuo Takayanagi Yukitoshi Otani Norihiro Umeda 《Optical Review》2003,10(2):128-130
Many studies have reported on the use of quartz tuning forks (a type of crystal oscillator used in wristwatches) in the detection of shear force, employed to control the distance between the probe and the sample in a scanning near-field optical microscope. This study focuses on a newly-devised shear force detection method capable of simultaneous non-external oscillation and detection, which also allows for subsequent reuse of a tuning fork. The optimum configuration and tip length for inserting a probe into the slit of a tuning fork have been elucidated. The shear force was detectable in about 5 nm decay length using such conditions. 相似文献
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为了进一步提高基于泛频振动的石英增强光声光谱测声器探测灵敏度,在一次泛频振动模式下采用一个比商用标准音叉外形尺寸大5倍的定制大音叉,并对其性能进行优化.通过理论和实验研究得出了音叉与激光的最佳作用位置,发现音叉的一次泛频振动有两个波腹点,且在距离音叉根部8 mm处,音叉振臂的振动幅度最大.微型声音谐振腔由三种不同内径的不锈钢毛细管加工而成,与音叉组成共轴配置石英增强光声光谱光谱测声器,用来进一步增强信号幅值.在最佳微型声音谐振腔配置下,获得了30倍的信号增益因子,有效提高了石英增强光声光谱光谱测声器的探测灵敏度. 相似文献
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频域光学相干层析系统中扫描机构定位精度、 机械抖动及样品移动会造成A扫描信号幅值和相位发生波动, 影响生物组织成像质量. 利用最小灰度差匹配、Lorentzian曲线极值拟合和谱域光程差补偿等方法对A 扫描信号进行幅值配准. 通过对A扫描信号相位分布特征的匹配实现相位差检测与配准. 通过求已配准的A 扫描复信号之差, 消除静态组织对血流成像的影响. 进行了人眼扫描实验, 有效提取了视网膜三维血流图像. 实验结果表明, 提出的幅值及相位配准方法大大减小了系统扫描精度、人眼跳动等因素对生物组织在体成像质量的影响. 快速、精确的相位配准方法也可广泛应用在多普勒OCT、相位显微等与相位分辨有关的光学成像领域.
关键词:
频域光学相干层析
配准
血流成像
相位分布特征 相似文献
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针尖 样品的距离控制系统是扫描近场红外显微镜的重要组成部分。切变力探测作为一种重要的近场距离控制手段而得到了广泛的应用。介绍了一种对切变力探测系统的改进方法 ,它可以有效地提高石英晶振音叉的品质因数 ,进而提高探测系统对切变力感应的灵敏度。给出了理论分析和实验验证结果 相似文献
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A new H-type gyroscope using a single LiTaO3 crystal that combines the H-type vibrational mode with a tuning fork type vibrational mode is proposed. This greatly suppresses leakage output from the piezoelectric gyroscope and also improves stability. The operation in the drive mode non-resonant condition and detection mode resonance condition is also proposed. It is possible to increase the sensor sensitivity remarkably because the drive voltage can be increased. In addition, an equivalent circuit constant including the leakage output could be accurately deduced. Automatic compensation of temperature characteristic for angular velocity detection sensitivity and drift is examined with the simple equivalent circuit. By adding a new sensor that detects the drive vibrational mode, we can produce a stable reference signal for the phase detection of output. This shows that it is possible to greatly improve the temperature characteristic of sensitivity and drift. 相似文献
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N. Petra J. Zweck A. A. Kosterev S. E. Minkoff D. Thomazy 《Applied physics. B, Lasers and optics》2009,94(4):673-680
Quartz-enhanced photoacoustic spectroscopy (QEPAS) sensors are based on a recent approach to photoacoustic detection which
employs a quartz tuning fork as an acoustic transducer. These sensors enable detection of trace gases for air quality monitoring,
industrial process control, and medical diagnostics. To detect a trace gas, modulated laser radiation is directed between
the tines of a tuning fork. The optical energy absorbed by the gas results in a periodic thermal expansion which gives rise
to a weak acoustic pressure wave. This pressure wave excites a resonant vibration of the tuning fork thereby generating an
electrical signal via the piezoelectric effect. This paper describes a theoretical model of a QEPAS sensor. By deriving analytical
solutions for the partial differential equations in the model, we obtain a formula for the piezoelectric current in terms
of the optical, mechanical, and electrical parameters of the system. We use the model to calculate the optimal position of
the laser beam with respect to the tuning fork and the phase of the piezoelectric current. We also show that a QEPAS transducer
with a particular 32.8 kHz tuning fork is 2–3 times as sensitive as one with a 4.25 kHz tuning fork. These simulation results
closely match experimental data. 相似文献