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 31 for “"optical contrast"”.
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Functional Biological Spectroscopy and Multiphoton Imaging Using Endogenous Optical Contrast
Endogenous optical signatures of tissue provide information relevant to biological and biomedical questions through measurements of intracellular and extracellular endogenous contrast. To develop sensitive diagnostic methods using this contrast, the important individual endogenous constituents were …
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Optical contrast between transparent materials through external modulation of the Faraday effect
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
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Delivery of molecular-specific optical contrast agents for cancer biomarker detection in live cells and tissues
Molecular-specific optical contrast agents have shown promise as potential non-invasive probes for the detection of cancer and its precursors. The topical use of optical contrast agents in vivo has been hindered, however, by the difficulty of delivering macromolecules through mucosal tissue. My …
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MoS2 on Gold: achieving extremely high exfoliation yield and optical contrast for Van der Waals monolayers
… work was carried out to improve the yield and optical contrast of exfoliated two-dimensional (2D) Van der Waals (VdWs) materials. Molybdenum disulphide (MoS2) on gold (Au) is investigated in detail as it provides an extremely large exfoliation yield and a high optical contrast. These techniques …
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Deep learning for nanofluidic scattering microscopy
… optics, such that the nanochannels improve the optical contrast of the imaged biomolecules by several orders of magnitude. A video of the total scattering intensity is then recorded with a high frame rate camera (capturing 200 fps) in order to capture the movement of the molecules as well as the …
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Application of p electron theory to predict new materials for rewritable optical recording
… is distinguished from the difference in the optical properties of the two states. Until now most alloys utilised in optical data storage are based on ternary GeSbTe and the quartenary AgIn-Sb2Te alloys. To ensure that optical data storage remains competitive, new alloys with superior …
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Scattering Scanning Near-Field Optical Microscopy on Anisotropic Dielectrics
Near-field optical microscopy allows the nondestructive examination of surfaces with a spatial resolution far below the diffraction limit of Abbe. In fact, the resolution of this kind of microscope is not at all dependent on the wavelength, but is typically in the range of 10 to 100 nanometers. On …
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Methods to Tailor Protein Microspheres for Biomedical Applications
… have resulted in the first class of optical contrast agents for optical coherence tomography (OCT). Modifications with receptor specific peptides have generated microspheres that can be targeted to tumor cells. And finally, modifications of the microspheres with nucleic acids have …
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Electronic and optical properties of phase change alloys studied with ab initio methods
… correlation between structural, electronic and optical properties of so-called phase-change materials is studied. Employing methods of computational physics, in particular density functional theory and many-body perturbation theory this work reveals the correlation between the change of the …
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Nanoshells in vivo imaging using two-photon excitation microscopy
This thesis describes the development and optical characterization of near infrared (NIR) gold nanoshells for the use as luminescent contrast agents for applications in small animal blood vessel imaging. Two types of gold-silica nanoshells excitable by NIR lasers are investigated: Type 1 nanoshells …
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Developing transition metal dichalcogenide alloys for applications to integrated photonics
… (PIC). We measure the near-infrared (NIR) optical properties of bulk crystal telluride TMDs and sulfide TMDs. We find that telluride TMDs have large optical density and large optical contrast, but the loss is too high. The sulfide TMDs have lower loss, but the phase change energy is much …
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Combinatorial material synthesis applied to Ge-Sb-Te based phase change materials
… erased and re- written repetitively using optical techniques. They can be characterized by two stable physical structures that exhibit significantly different optical properties. Further optimisation of this technology requires the determination of crystallisation kinetics and comprehensive …
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Photoacoustic image reconstruction to solve the acoustic inverse problem with deep learning
… superficial tumors. It combines the strengths of optical imaging and ultrasound: high optical contrast as well as high imaging depth and spatial resolution. Handheld PA devices, which are popular due to their versatility and ease of use, only provide a limited field of view caused by their sensor …
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Uniaxial optical phase change metamaterials
Optical metamaterials are artificially engineered materials with exceptional electromagnetic properties that cannot be found in nature. Over the last 20 years, optical metamaterials have driven forward a plethora of fields from telecommunications to solar energy harvesting. They owe their unique …
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Enabling Biomedical Imaging Diagnostics using Optical Methods
<p>This thesis work applies optical schemes to existing biomedical imaging techniques to improve the performance of present state-of-the-art biomedical imagers, and is in two parts. In the first part, a fast and simple optical time-gate scheme for counting single photons is presented. The gate is …
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Imaging through scattering
… thesis we demonstrate novel methods to overcome optical scattering in order to resolve information about hidden scenes, in particular for biomedical applications. Imaging through scattering media has long been a challenge, as scattering corrupts scenes in a non-invertible way. The use of …
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Mathematical models for bistable nematic liquid crystal displays
… two (or more) stable field-free states that are optically-distinct means that contrast can be maintained in a display without an externally-applied electric field. An applied field is required only to switch the device from one state to the other, as needed. This dissertation focuses on …
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PUSH-PULL COPOLYMERS IN THIN FILM FOR ELECTRONIC APPLICATION
… of electrochromic devices, featuring an optical contrast of 29%. In the same way, it was possible to fabricate novel electrochromic devices by combining NDI2ODT4 with the novel system bis-thiophene fulleropyrrolidine (bis-Th2P-C60). Moreover, it was also possible to demonstrate that …
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A Monte Carlo ray trace tool for predicting contrast in naval scenes including the effects of polarization
… thesis evaluates the extent of threat due to optical contrast with the ocean background. As part of this effort, an MCRT tool was created that allows the user to vary the shape and surface properties of a ship. A reverse MCRT was performed in order to reduce the processing time required to get …
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Quantitative frequency-domain fluorescence spectroscopy in tissues and tissue-like media
… technology at lower cost, modern near-infrared optical spectroscopy offers the possibility of inexpensive technology for quantitative and non-invasive diagnoses. Hemoglobin is the dominant chromophore in the 700-900 nm spectral region and as such it allows for the optical assessment of …
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