Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"evanescent wave"”.
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Development of the Evanescent Wave Atomic Force Microscope
… provide real time separation information. The evanescent wave atomic force microscope (EW-AFM) utilizes a second, independent detection system to determine absolute probe-surface separation in real time. The EW-AFM can simultaneously acquire real-time force and probe-sample separation …
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Two Studies in Evanescent Wave Propagation (Beam, Acoustic, Gaussian)
… penny-shape crack, are investigated. First, wave-front approximations to the emissions generated by the sudden growth of a tensile crack in the unbounded elastic solid are reviewed. These approximations are then Fourier transformed to give the high-frequency portion of their spectra. Second, …
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Evanescent wave spectroscopy for detection of water and water treeing in polymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
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Investigation of Non-DLVO Forces using an Evanescent Wave Atomic Force Microscope
… new methods for measuring surface forces using evanescent waves, and applications to non-DLVO forces. An evanescent wave, generated at a solid-liquid interface, is scattered by AFM tips or particles attached to AFM cantilevers. The scattering of this wave is used to determine absolute separation …
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Composite Films for Modifying Evanescent Wave Characteristics in Long-Period Grating Biosensors
… Microscopy. The affinity film was probed by an evanescent wave to detect changes in refractive index due to the binding of anti-BSA IgG. Under these conditions, the sensor yielded a signal ratio of approximately 10-4 refractive index units per nm signal. Reproducible binding was shown over …
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Evanescent Wave Reduction Using a Segmented Wavemaker in a Two Dimensional Wave Tank
Evanescent waves are created by the wavemaking process during tank testing. They have long been a nuisance for engineers as they contaminate the wave field in the tank and result in additional inertial force experienced by a wavemaker. Evanescent waves are created by the mismatch between the motion …
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The control of gold and latex particles on optical waveguides
… to the trapping of a small number of particles. Evanescent wave trapping allows simultaneous trapping of many particles due to the long length over which a strong intensity gradient is present. A channel waveguide used to produce such an evanescent wave can be photolithographically defined on a …
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A study of three transition metal compounds and their applications
… of 3d electrons in Fe^{2+} ion indirectly. Evanescent wave was discovered to be able to tunnel through a negative reflectance index material and gets strengthened inside an alternating metal-high K material 1d photonic crystal structure. Where the regular light eventually fails in sub-micron …
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Electric Field Manipulation of Gold Nanorods: Characterization of Far-Field Alignment and Spatial Positioning Through Optical Response Imaging Techniques
… electric fields. Under the conditions of TIR, an evanescent wave is generated by the total reflection of incident light at a glass-water interface. This electromagnetic field decays rapidly from the interface, penetrating to a distance of 100 nm into the sample. The result is high resolution, …
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Methane in deep sea hydrothermal plumes. Development of a new in-situ methane sensing technology
… of dissolved methane; Near Infrared Fibre-optic Evanescent Wave Spectroscopy (FEWS) and Surface Plasmon Resonance (SPR). No detection (at the µM level) was possible with FEWS, but the second technique using SPR sensors associated with a methane specific binding chemically showed great promise. A …
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Numerical characterisation of label free optical biosensors
… are all suitable for deep-probe sensing as large evanescent field can be excited in the sensing medium with substantial penetration depth achieved by techniques like Surface Plasmon Resonance (SPR) and sensor architectures based on nanowires and slot waveguides. This thesis presents three …
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Quantitative Materials Contrast at High Spatial Resolution With a Novel Near-Field Scanning Microwave Microscope
A novel Near-Field Scanning Microwave Microscope (NSMM) has been developed where a Scanning Tunneling Microscope (STM) is used for tip-to-sample distance control. The technique is non-contact and non-destructive. The same tip is used for both STM and NSMM, and STM helps maintain the tip-to-sample …
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In-situ cure monitoring of epoxy resin systems
… was successfully used in two ways: i) as an evanescent absorption sensor to monitor specific absorption bands of the resin system. The absorption of energy from the evanescent wave of the optical fibre by absorbing media allows evanescent absorption spectra to be obtained. Absorption spectra …
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Mid-Infrared Integrated Devices for Optical Chemical Sensing
… novel method and system based on MIR fibre-optic evanescent- wave spectroscopy, which enables enhanced detection of volatile organic compounds (VOCs). Here, a nanoporous silicon cladding was used to reversibly concentrate molecules close to the fibre surface, thus enhancing VOC detection. A …
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Biochemical sensing using Siloxane polymer waveguides
… here is to extend the capabilities of siloxane waveguide technology in the field of biochemical sensing. Recent advances in the integration of polymeric optical waveguides with electronics onto standard printed circuit boards (PCBs) allow the formation of cost-effective lab-on-achip modules …
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A Dy:YAG coated fiber optic thermal sensor - proof of concept
… mechanism used to excite the Dy: YAG is the evanescent wave coupling of the guided pump radiation out of the core and into the coating. This mechanism was utilized to produce bound rays within the fiber from the Dy: YAG emission signal which in turn are guided to a detector. The pump …
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Experimental investigations of the role of proximity approximation in near-field radiative transfer
… comparable to or smaller than the characteristic wavelength given by Wien's displacement law. At larger gaps, conventional theory of blackbody radiation is sufficient to describe the radiative transfer; at smaller gaps, however, wave effects such as evanescent wave tunneling, interference and …
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Excitation, Interaction, and Scattering of Localized and Propagating Surface Polaritons
… providing single-molecule sensitivity. The sub-wavelength-confined strong electromagnetic field associated with a SPR provides the basis for scattering-type near-field optical microscopy or tip-enhanced Raman spectroscopy, where the metal particle serves as a probe that is scanned laterally in …
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