Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Electronic Theses and Dissertations

Discipline
Institution
Keyword
Publication Year
File Type

Articles 3511 - 3540 of 4194

Full-Text Articles in Physical Sciences and Mathematics

Discrimination Of Automobile Carpet Fibers Using Multiple Analytical Techniques And The Subsequent Creation Of A Searchable Data, Derek Dorrien Jan 2006

Discrimination Of Automobile Carpet Fibers Using Multiple Analytical Techniques And The Subsequent Creation Of A Searchable Data, Derek Dorrien

Electronic Theses and Dissertations

Forensic fiber examination is an important part of trace evidence analysis. Fibers may be recovered from a crime scene that could link a particular suspect to the scene. Clothing fibers are most frequently encountered but automobile carpeting fibers may also be recovered. An understanding of the frequency of occurrence and the discrimination power of different analytical techniques is needed in order to better establish the evidentiary value of automobile carpet fiber evidence. Seventy-five automobile carpet fiber samples were analyzed using a series of techniques ranging from nondestructive to destructive. These techniques included polarized light microscopy, fluorescence microscopy, microspectrophotometry, Fourier-transform infrared …

Go to article

Object Association Across Multiple Moving Cameras In Planar Scenes, Yaser Sheikh Jan 2006

Object Association Across Multiple Moving Cameras In Planar Scenes, Yaser Sheikh

Electronic Theses and Dissertations

In this dissertation, we address the problem of object detection and object association across multiple cameras over large areas that are well modeled by planes. We present a unifying probabilistic framework that captures the underlying geometry of planar scenes, and present algorithms to estimate geometric relationships between different cameras, which are subsequently used for co-operative association of objects. We first present a local1 object detection scheme that has three fundamental innovations over existing approaches. First, the model of the intensities of image pixels as independent random variables is challenged and it is asserted that useful correlation exists in intensities of …

Go to article

Quantitative High-Angle Annular Dark Field Scanning Transmission To Electron Microscopy For Materials Science, Rumyana Petrova Jan 2006

Quantitative High-Angle Annular Dark Field Scanning Transmission To Electron Microscopy For Materials Science, Rumyana Petrova

Electronic Theses and Dissertations

Scanning transmission electron microscopy (STEM) has been widely used for characterization of materials; to identify micro- and nano-structures within a sample and to analyze crystal and defect structures. High-angle annular dark field (HAADF) STEM imaging using atomic number (Z) contrast has proven capable of resolving atomic structures with better than 2 A lateral resolution. In this work, the HAADF STEM imaging mode is used in combination with multislice simulations. This combination is applied to the investigation of the temperature dependence of the intensity collected by the HAADF detector in silicon, and to convergent beam electron diffraction (CBED) to measure the …

Go to article

Algorithms For Discovering Communities In Complex Networks, Hemant Balakrishnan Jan 2006

Algorithms For Discovering Communities In Complex Networks, Hemant Balakrishnan

Electronic Theses and Dissertations

It has been observed that real-world random networks like the WWW, Internet, social networks, citation networks, etc., organize themselves into closely-knit groups that are locally dense and globally sparse. These closely-knit groups are termed communities. Nodes within a community are similar in some aspect. For example in a WWW network, communities might consist of web pages that share similar contents. Mining these communities facilitates better understanding of their evolution and topology, and is of great theoretical and commercial significance. Community related research has focused on two main problems: community discovery and community identification. Community discovery is the problem of extracting …

Go to article

Collaboration Enforcement In Mobile Ad Hoc Networks, Ning Jiang Jan 2006

Collaboration Enforcement In Mobile Ad Hoc Networks, Ning Jiang

Electronic Theses and Dissertations

Mobile Ad hoc NETworks (MANETs) have attracted great research interest in recent years. Among many issues, lack of motivation for participating nodes to collaborate forms a major obstacle to the adoption of MANETs. Many contemporary collaboration enforcement techniques employ reputation mechanisms for nodes to avoid and penalize malicious participants. Reputation information is propagated among participants and updated based on complicated trust relationships to thwart false accusation of benign nodes. The aforementioned strategy suffers from low scalability and is likely to be exploited by adversaries. To address these problems, we first propose a finite state model. With this technique, no reputation …

Go to article

All-Semiconductor High Power Mode-Locked Laser System, Kyungbum Kim Jan 2006

All-Semiconductor High Power Mode-Locked Laser System, Kyungbum Kim

Electronic Theses and Dissertations

All-optical synchronization and its application in advanced optical communications have been investigated in this dissertation. Dynamics of all-optical timing synchronization (clock recovery) using multi-section gain-coupled distributed-feedback (MS-GC DFB) lasers are discussed. A record speed of 180-GHz timing synchronization has been demonstrated using this device. An all-optical carrier synchronization (phase and polarization recovery) scheme from PSK (phase shift keying) data is proposed and demonstrated for the first time. As an application of all-optical synchronization, the characterization of advanced modulation formats using a linear optical sampling technique was studied. The full characterization of 10-Gb/s RZ-BPSK (return-to-zero binary PSK) data has been demonstrated. …

Go to article

Probing Random Media With Singular Waves, Chaim Schwartz Jan 2006

Probing Random Media With Singular Waves, Chaim Schwartz

Electronic Theses and Dissertations

In recent years a resurgence of interest in wave singularities (of which optical vortices are a prominent example), light angular momentum and the relations between them has occurred. Many applications in various areas of linear and non-linear optics have been based on studying effects related to angular momentum and optical vortices. This dissertation examines the use of such wave singularities for studying the light propagation in highly inhomogeneous media and the relationship to angular momentum transfer. Angular momentum carried by light can be, in many cases, divided in two terms. The first one relates to the polarization of light and …

Go to article

Contrasting Chemical Response To Experimental Acidification Of Five Acid-Sensitive Streams, Heather Vanessa Goss Jan 2006

Contrasting Chemical Response To Experimental Acidification Of Five Acid-Sensitive Streams, Heather Vanessa Goss

Electronic Theses and Dissertations

To evaluate the role of stream water and substrates in response to acidification, we experimentally acidified five first-order streams in 2005: East Bear Brook, Hadlock Brook, and Mud Pond Inlet (Maine, USA); Fernow WS3 (West Virginia, USA); and Lesní Potok (Czech Republic). All have forested catchments and low alkalinity water. We evaluated water samples from a reference site above the point of hydrochloric acid addition and from two or three sites located 16 to 94 m downstream. Just before acid addition we collected streambed sediment samples for sequential extraction of metals. Several sediment-water and aqueous processes contributed to neutralization of …

Go to article

Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown Jan 2006

Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown

Electronic Theses and Dissertations

A high-temperature region associated with Acadian deformation extends 200 km through north-central New England. The scale of this heat source is investigated in order to better understand the rheology and mechanics of deforming orogens. In central Maine, on the boundary of the high-temperature region, isograds in pelitic rocks are normal to the accretionary structures and record a steep northeast-southwest thermal gradient. The isogradic sequence, geobarometry, and the mineral assemblages indicate low-pressure, high-temperature metamorphism, moderately low pressures of 3 kbar, and temperatures ranging from 600º to 450ºC over a 10 km region. The spacing between these isograds and the temperature at …

Go to article

Sauger Population Ecology In Three Missouri River Mainstem Reservoirs, Brian D. S. Graeb Jan 2006

Sauger Population Ecology In Three Missouri River Mainstem Reservoirs, Brian D. S. Graeb

Electronic Theses and Dissertations

Sauger Sander canadensis populations have experienced widespread declines across much of their range. Factors suspected to contribute to these declines include hybridization, exploitation, loss of spawning areas, and general habitat alterations associated with regulated rivers. Several sauger populations within the Missouri River basin are also experiencing similar declines, particularly in the headwaters of Montana, and the lower basin states of Nebraska and Missouri. However, sauger populations in many of the reservoirs in South Dakota (between Montana and the lower basin) have relatively stable populations. Given the paucity of information on factors influencing sauger population ecology in general, and Missouri River …

Go to article

Archaeological Geology And Postglacial Development Of The Central Penobscot River Valley, Maine, Usa, Alice Repsher Kelley Jan 2006

Archaeological Geology And Postglacial Development Of The Central Penobscot River Valley, Maine, Usa, Alice Repsher Kelley

Electronic Theses and Dissertations

The purpose of this interdisciplinary study is to provide a geological and environmental context for the Late Pleistocene and Holocene Native American occupation of the central Penobscot River Valley, Maine. In addition, this work provides a model for the regional synthesis of geological, archaeological, and paleoenvironmental data in order to examine large-scale patterns of archaeological site formation and preservation. The postglacial central Penobscot Valley experienced varied and rapid landscape changes. Withdrawal of the Laurentide Ice Sheet was followed by marine transgression and regression. Subaerial exposure initiated landscape development. The postglacial Penobscot River rapidly excavated a channel through glacial sediments, creating …

Go to article

A Geochemical, Isotopic, And Petrologic Study Of A Watershed With Arsenic-Enriched Ground Water In Northport, Maine, Gail Elizabeth Lipfert Jan 2006

A Geochemical, Isotopic, And Petrologic Study Of A Watershed With Arsenic-Enriched Ground Water In Northport, Maine, Gail Elizabeth Lipfert

Electronic Theses and Dissertations

High mean arsenic concentrations up 26.6 ¹mol/L (1990 ¹g/L) occur in ground water within a watershed at Kelly's Cove, Northport, Maine, USA. The Kelly's Cove watershed is a fractured-bedrock system composed of sul¯dic schist with granitic to dioritic intrusions. Arsenic is enriched in these rocks up to 1050 mg kg¡1 (average: 68 mg kg¡1). The distribution of arsenic in the bedrock appears to be controlled by the presence of arsenopyrite and arsenian pyrite, that occur primarily in post-metamorphic, tourmaline + quartz § carbonate veins and the Kelly's Cove granite. Based on the metamorphic signature of the tourmaline chemistry and the …

Go to article

Spatial And Temporal Changes In Stream Chemistry At Three Watersheds During High Discharge Episodes, Mollie Kate Laird Jan 2006

Spatial And Temporal Changes In Stream Chemistry At Three Watersheds During High Discharge Episodes, Mollie Kate Laird

Electronic Theses and Dissertations

A longitudinal study of first order streams in three forested watersheds was conducted to determine spatial and temporal trends in geochemistry during high discharge acidic episodes. The watersheds were East Bear Brook and Hadlock Brook (Maine, USA), and Fernow WS3 (West Virginia, USA). Watersheds were selected based on soil type, stream pH, and historical chemistry. Stream sampling sites were distributed along an elevational gradient and sampled simultaneously during a high discharge episode. Base flow samples were collected prior to the start of the hydrological event. The Maine watersheds, East Bear Brook and Hadlock Brook, were sampled during fall 2005 rain …

Go to article

Vascular Morphometry Of The Retina In Antarctic Fishes Is Dependent Upon The Level Of Hemoglobin In Circulation, Jody M. Wujcik Jan 2006

Vascular Morphometry Of The Retina In Antarctic Fishes Is Dependent Upon The Level Of Hemoglobin In Circulation, Jody M. Wujcik

Electronic Theses and Dissertations

Antarctic notothenioids express the circulating oxygen-binding protein hemoglobin (Hb) over a broad range of blood concentrations. White-blooded icefishes (Suborder: Notothenioidei, Family: Channichthyidae) are the only known adult vertebrates to lack Hb completely. In addition to its role in oxygen transport, Hb is the primary reactant in degradation of nitric oxide (NO). Thus, NO should be degraded at a slower rate in Hb-lacking icefishes than in Hb-expressing notothenioids, leading to higher steady-state levels of NO in the former group. Increased levels of NO should stimulate upregulation of angiogenesis, the growth and proliferation of new blood vessels from existing vasculature. Based upon …

Go to article

Additive Lithography Fabrication And Integration Of Micro Optics, Mahesh Pitchumani Jan 2006

Additive Lithography Fabrication And Integration Of Micro Optics, Mahesh Pitchumani

Electronic Theses and Dissertations

Optical elements are the fundamental components in photonic systems and are used to transform an input optical beam into a desired beam profile or to couple the input beam into waveguides, fibers, or other optical systems or devices. Macroscopic optical elements are easily fabricated using grinding and polishing techniques, but few methods exist for inexpensive fabrication of micro optical elements. In this work we present an innovative technique termed Additive Lithography that makes use of binary masks and controlled partial exposures to sculpt photoresist into the desired optical surface relief profile. We explore various masking schemes for fabricating a variety …

Go to article

Radiation Studies Of The Tin-Doped Microscopic Droplet Laser Plasma Light Source Specific To Euv Lithography, Chiew-Seng Koay Jan 2006

Radiation Studies Of The Tin-Doped Microscopic Droplet Laser Plasma Light Source Specific To Euv Lithography, Chiew-Seng Koay

Electronic Theses and Dissertations

Extreme ultraviolet lithography(EUVL) is being developed worldwide as the next generation technology to be inserted in ~ 2009 for the mass production of IC chips with feature sizes <35 nm. One major challenge to its implementation is the development of a 13.5 nm EUV source of radiation that meets the requirements of current roadmap designs of the source of illumination in commercial EUVL scanners. The light source must be debris-free, in a free-space environment with the imaging EUV optics that must provide sufficient, narrow spectral band EUV power to print 100 wafers/hr. To meet this need, extensive studies on emission from a laser plasma source utilizing tin-doped droplet target was conducted. Presented in this work, are the many optical techniques such as spectroscopy, radiometry, and imaging, that were employed to characterize and optimize emission from the laser plasma source State of the art EUV spectrographs were employed to observe the source's spectrum under various laser irradiation conditions. Comparing the experimental spectra to those from theory, has allowed the determination of the Sn ion stages responsible for emitting into the useful EUV bandwidth. Experimental results were compared to spectral simulations obtained using Collisional-Radiative Equilibrium (CRE) model, as well. Moreover, extensive measurements surveying source emission from 2 nm to 30 nm, which is the region of the electromagnetic spectrum defined as EUV, was accomplished. Absolutely calibrated metrology was employed with the Flying Circus instrument from which the source's conversion efficiency (CE)--from laser to the useful EUV energy--was characterized under various laser irradiation conditions. Hydrodynamic simulations of the plasma expansion together with the CRE model predicted the condition at which optimum conversion could be attained. The condition was demonstrated experimentally, with the highest CE to be slightly above 2%, which is the highest value among all EUV source contenders. In addition to laser intensity, the CE was found to depend on the laser wavelength. For better understanding, this observation is compared to results from simulations. Through a novel approach in imaging, the size of the plasma was characterized by recording images of the plasma within a narrow band, around 13.5 nm. The size, approximately 100 ìm, is safely within the etendue limit set by the optical elements in the EUV scanner. Finally, the notion of irradiating the target with multiple laser beams was explored for the possibility of improving the source's conversion efficiency.

Go to article

Analytical Potential Of Polymerized Liposomes Bound To Lanthanide Ions For Qualitative And Quantitative Analysis Of Proteins, Marina Santos Jan 2006

Analytical Potential Of Polymerized Liposomes Bound To Lanthanide Ions For Qualitative And Quantitative Analysis Of Proteins, Marina Santos

Electronic Theses and Dissertations

One of the intriguing features of biological systems is the prevalence of highly selective and often very strong interactions among different cellular components. Such interactions play a variety of organizational, mechanical, and physiological roles at the cellular and organism levels. Antigen-antibody complexes are representative examples of highly selective and potent interactions involving proteins. The marked specificity of protein-antibody complexes have led to a wide range of applications in cellular and molecular biology related research. They have become an integral research tool in the present genomic and proteomic era. Unfortunately, the production of selective tools based on antigen-antibody interactions requires cumbersome …

Go to article

Fade Statistics For A Lasercom System And The Joint Pdf Of A Gamma-Gamma Distributed Irradiance And Its Time Derivative, Frida Stromqvist Vetelino Jan 2006

Fade Statistics For A Lasercom System And The Joint Pdf Of A Gamma-Gamma Distributed Irradiance And Its Time Derivative, Frida Stromqvist Vetelino

Electronic Theses and Dissertations

The performance of lasercom systems operating in the atmosphere is reduced by optical turbulence, which causes irradiance fluctuations in the received signal. The result is a randomly fading signal. Fade statistics for lasercom systems are determined from the probability density function (PDF) of the irradiance fluctuations. The expected number of fades per second and their mean fade time require the joint PDF of the fluctuating irradiance and its time derivative. Theoretical integral expressions, as well as closed form, analytical approximations, were developed for the joint PDF of a gamma-gamma distributed irradiance and its time derivative, and the corresponding expression for …

Go to article

Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou Jan 2006

Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou

Electronic Theses and Dissertations

Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in next-generation Internet architectures. This dissertation addresses the important issues of improving four aspects of optical networks, namely, routing efficiency, fairness, differentiated quality of service (QoS) and throughput. A new approach for implementing efficient routing and wavelength assignment in WDM networks is proposed and evaluated. In this approach, the state of a multiple-fiber link is represented by a compact bitmap computed as the logical union of the bitmaps of the free wavelengths in the fibers of this link. A modified Dijkstra's shortest path algorithm and a wavelength …

Go to article

Radon In Ground Water: A Study Of The Measurement And Release Of Waterborne Radon And Modeling Of Radon Variation In Bedrock Wells, Vincente E. Guiseppe Jan 2006

Radon In Ground Water: A Study Of The Measurement And Release Of Waterborne Radon And Modeling Of Radon Variation In Bedrock Wells, Vincente E. Guiseppe

Electronic Theses and Dissertations

Naturally occurring radon gas (222Rn) exists in ground water and drinking water supplies. Research involving radon in ground water requires the ability to accurately measure radon in water. In the absence of a national program, an intercomparison study of laboratories was sanctioned by the State of Maine. The University of Maine research laboratory supplied each laboratory with water samples of various radon concentrations, served as the reference laboratory, and analyzed the results presented here. The external review of the University of Maine laboratory and agreement with some of the participating laboratories verifies its accuracy in measuring radon in water. A …

Go to article

Mathematical Modeling Of Smallpox Withoptimal Intervention Policy, Niwas Lawot Jan 2006

Mathematical Modeling Of Smallpox Withoptimal Intervention Policy, Niwas Lawot

Electronic Theses and Dissertations

In this work, two differential equation models for smallpox are numerically solved to find the optimal intervention policy. In each model we look for the range of values of the parameters that give rise to the worst case scenarios. Since the scale of an epidemic is determined by the number of people infected, and eventually dead, as a result of infection, we attempt to quantify the scale of the epidemic and recommend the optimum intervention policy. In the first case study, we mimic a densely populated city with comparatively big tourist population, and heavily used mass transportation system. A mathematical …

Go to article

Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton Jan 2006

Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton

Electronic Theses and Dissertations

Antenna-coupled detectors provide uncooled, cost-effective solutions for infrared and millimeter-wave imaging. This work describes the design, fabrication, measurement, and optimization of several types of antenna-coupled detectors for LWIR (8 - 12 µm) and 94 GHz radiation. Two types of millimeter-wave antenna-coupled detectors were fabricated and tested: a slot antenna coupled to a bolometer, and a patch antenna coupled to a SiC Schottky diode. Electromagnetic modeling of the antennas helped guide the design of antennas with better impedance matching to the detectors. Schottky diodes are discussed as detectors for millimeter-wave and infrared radiation, with the goal of increasing the cutoff frequency …

Go to article

Integrated Wavelength Stabilization Of Broad Area Semiconductor Lasers Using A Dual Grating Reflector, Jason O'Daniel Jan 2006

Integrated Wavelength Stabilization Of Broad Area Semiconductor Lasers Using A Dual Grating Reflector, Jason O'Daniel

Electronic Theses and Dissertations

A new fully integrated wavelength stabilization scheme based on grating-coupled surface-emitting lasers is explored. This wavelength stabilization scheme relies on two gratings. The first grating is fabricated on the p-side of the semiconductor laser in close proximity to the laser waveguide such that it couples light out of the guided mode of the waveguide into a propagating mode in the substrate; this grating is known as the grating coupler. The second grating is fabricated on the n-side of the substrate such that for the stabilization wavelength, this second grating operates in the Littrow condition and is known as the feedback …

Go to article

Multiple View Geometry For Video Analysis And Post-Production, Xiaochun Cao Jan 2006

Multiple View Geometry For Video Analysis And Post-Production, Xiaochun Cao

Electronic Theses and Dissertations

Multiple view geometry is the foundation of an important class of computer vision techniques for simultaneous recovery of camera motion and scene structure from a set of images. There are numerous important applications in this area. Examples include video post-production, scene reconstruction, registration, surveillance, tracking, and segmentation. In video post-production, which is the topic being addressed in this dissertation, computer analysis of the motion of the camera can replace the currently used manual methods for correctly aligning an artificially inserted object in a scene. However, existing single view methods typically require multiple vanishing points, and therefore would fail when only …

Go to article

Sensor-Based Computing Techniques For Real-Time Traffic Evacuation Management, Georgiana Hamza-Lup Jan 2006

Sensor-Based Computing Techniques For Real-Time Traffic Evacuation Management, Georgiana Hamza-Lup

Electronic Theses and Dissertations

The threat of terrorist incidents is higher than ever before and devastating acts, such as the terrorist attacks on the World Trade Center and the Pentagon, have left many concerns about the possibility of future incidents and their potential impact. Unlike some natural disasters that can be anticipated, terrorist attacks are sudden and unexpected. Even if sometimes we do have partial information about a possible attack, it is generally not known exactly where, when, or how an attack will occur. This lack of information posses great challenges on those responsible for security, specifically, on their ability to respond fast, whenever …

Go to article

Image-Based Material Editing, Erum Khan Jan 2006

Image-Based Material Editing, Erum Khan

Electronic Theses and Dissertations

Photo editing software allows digital images to be blurred, warped or re-colored at the touch of a button. However, it is not currently possible to change the material appearance of an object except by painstakingly painting over the appropriate pixels. Here we present a set of methods for automatically replacing one material with another, completely different material, starting with only a single high dynamic range image, and an alpha matte specifying the object. Our approach exploits the fact that human vision is surprisingly tolerant of certain (sometimes enormous) physical inaccuracies. Thus, it may be possible to produce a visually compelling …

Go to article

Syntax-Based Concept Extraction For Question Answering, Demetrios Glinos Jan 2006

Syntax-Based Concept Extraction For Question Answering, Demetrios Glinos

Electronic Theses and Dissertations

Question answering (QA) stands squarely along the path from document retrieval to text understanding. As an area of research interest, it serves as a proving ground where strategies for document processing, knowledge representation, question analysis, and answer extraction may be evaluated in real world information extraction contexts. The task is to go beyond the representation of text documents as "bags of words" or data blobs that can be scanned for keyword combinations and word collocations in the manner of internet search engines. Instead, the goal is to recognize and extract the semantic content of the text, and to organize it …

Go to article

Three-Photon Absorption Process In Organic Dyes Enhanced By Surface Plasmon Resonance, Ion Cohanoschi Jan 2006

Three-Photon Absorption Process In Organic Dyes Enhanced By Surface Plasmon Resonance, Ion Cohanoschi

Electronic Theses and Dissertations

Multi-photon absorption processes have received significant attention from the scientific community during the last decade, mainly because of their potential applications in optical limiting, data storage and biomedical fields. Perhaps, one of the most investigated processes studied so far has been two-photon absorption (2PA). These investigations have resulted in successful applications in all the fields mentioned above. However, 2PA present some limitations in the biomedical field when pumping at typical 2PA wavelengths. In order to overcome these limitations, three-photon absorption (3PA) process has been proposed. However, 3PA in organic molecules has a disadvantage, typical values of σ3' are small (10-81 …

Go to article

On The Use Of Variable Coherence In Inverse Scattering Problems, Erwan Baleine Jan 2006

On The Use Of Variable Coherence In Inverse Scattering Problems, Erwan Baleine

Electronic Theses and Dissertations

Even though most of the properties of optical fields, such as wavelength, polarization, wavefront curvature or angular spectrum, have been commonly manipulated in a variety of remote sensing procedures, controlling the degree of coherence of light did not find wide applications until recently. Since the emergence of optical coherence tomography, a growing number of scattering techniques have relied on temporal coherence gating which provides efficient target selectivity in a way achieved only by bulky short pulse measurements. The spatial counterpart of temporal coherence, however, has barely been exploited in sensing applications. This dissertation examines, in different scattering regimes, a variety …

Go to article

Design And Optimization Of Nano-Optical Elements By Coupling Fabrication To Optical Behavior, Raymond Rumpf Jan 2006

Design And Optimization Of Nano-Optical Elements By Coupling Fabrication To Optical Behavior, Raymond Rumpf

Electronic Theses and Dissertations

Photonic crystals and nanophotonics have received a great deal of attention over the last decade, largely due to improved numerical modeling and advances in fabrication technologies. To this day, fabrication and optical behavior remain decoupled during the design phase and numerous assumptions are made about "perfect" geometry. As research moves from theory to real devices, predicting device behavior based on realistic geometry becomes critical. In this dissertation, a set of numerical tools was developed to model micro and nano fabrication processes. They were combined with equally capable tools to model optical performance of the simulated structures. Using these tools, it …

Go to article

First Prev Next Last