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Vector Magneto-Optical Generalized Ellipsometry For Determining Magneto-Optical Properties Of Thin Films, Chad Briley 2016 University of Nebraska-Lincoln

Vector Magneto-Optical Generalized Ellipsometry For Determining Magneto-Optical Properties Of Thin Films, Chad Briley

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Modern growth techniques allow for highly complex nano scale thin films to be created. These new films possess highly anisotropic properties structurally, optically, and magnetically that are significantly different from that of their bulk counterparts and must be accurately characterized in order to optimize desired properties for applications in next generation devices. Current magnetometry techniques focus on high symmetry characterization, namely in and out of the sample plane, and therefore do not possess the capabilities to fully explore these anisotropic properties without complicated setups and multiple sample manipulations. The author describes a setup that combines generalized ellipsometry with an octu-pole ...


Photoluminescence Studies Of Amorphous Boron Carbide And Tungsten Diselenide Thin Films, David M. Allendorfer 2016 University of Nebraska - Lincoln

Photoluminescence Studies Of Amorphous Boron Carbide And Tungsten Diselenide Thin Films, David M. Allendorfer

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

For many years scientists and engineers have been researching semi-conducting materials for use in a broad array of electronic devices. With the growing demand for faster, smaller and more efficient electronics, new materials must be characterized and their properties quantified. The focus of this thesis is to develop a system to measure photoluminescence in opto-electronic materials. Photoluminescence measurements are important because it can give researchers valuable information about a material’s band structure. This thesis begins by presenting the carrier recombination mechanisms and how they apply to photoluminescence. A system was developed to measure photoluminescence spectroscopy. This system was tested ...


A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox 2016 University of Maine

A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox

Electronic Theses and Dissertations

We explored the capabilities of additive manufacturing using a photo-cured jetted material 3D printer to manufacture a milli-microfluidic device with direct application in microalgae Dunaliella sp growth and intracellular compounds biosynthesis tests. A continuous microbioreactor for microalgae culture was CAD designed and successfully built in 1 hour and 49 minutes using black photopolymer cured by UV and a support material. The microreactor was made up of 2 parts including the bioreactor itself and a microchannel network for culture media fluids and microalgae. Both parts were assembled to form a single unit. Additional optical and auxiliar components were added. An external ...


Investigation Of The Optical Properties Of Pbse/Pbx Nanocrystals For Photodetector Applications, Haley Ann Morris 2016 University of Arkansas, Fayetteville

Investigation Of The Optical Properties Of Pbse/Pbx Nanocrystals For Photodetector Applications, Haley Ann Morris

Theses and Dissertations

Lead selenide and lead selenide/lead sulfide core/shell nanocrystals were investigated for use in near infrared photodetectors. A colloidal synthesis method was used for both the core and core/shell configurations. The lead sulfide shell was examined in order to mitigate oxidation of the nanoparticle surface. Absorbance and photoluminescence spectra were measured at room temperature and 77 K, respectively. Transmission electron microscopy images were also obtained to confirm crystallography and size. Bulk lead selenide was simulated in WIEN2k utilizing the linear-augmented plane wave method of solving density functional theory to better understand the electronic structure of PbSe. The crystal ...


Design, Fabrication And Measurement Of A Plasmonic Enhanced Terahertz Photoconductive Antenna, Nathan Matthias Burford 2016 University of Arkansas, Fayetteville

Design, Fabrication And Measurement Of A Plasmonic Enhanced Terahertz Photoconductive Antenna, Nathan Matthias Burford

Theses and Dissertations

Generation of broadband terahertz (THz) pulses from ultrafast photoconductive antennas (PCAs) is an attractive method for THz spectroscopy and imaging. This provides a wide frequency bandwidth (0.1-4 THz) as well as the straightforward recovery of both the magnitude and phase of the transmitted and/or reflected signals. The achieved output THz power is low, approximately a few microwatts. This is due to the poor conversion of the femtosecond laser used as the optical pump to useable current inside the antenna semiconducting material. The majority of THz power comes from the photocarriers generated within ~ 100 nm distance from the antenna ...


Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix 2016 University of Arkansas, Fayetteville

Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix

Theses and Dissertations

As is commonly known, the world is full of technological wonders, where a multitude of electronic devices and instruments continuously help push the boundaries of scientific knowledge and discovery. These new devices and instruments of science must be utilized at peak efficiency in order to benefit humanity with the most advanced scientific knowledge. In order to attain this level of efficiency, the materials which make up these electronics, or possibly more important, the fundamental characteristics of these materials, must be fully understood. The following research attempted to uncover the properties and characteristics of a selected family of materials. Herein, zinc ...


Frequency Tunable Antennas And Surface Microwave Imaging System Using Microfluidic Reconfiguration Techniques, Abhishek Dey 2016 University of South Florida

Frequency Tunable Antennas And Surface Microwave Imaging System Using Microfluidic Reconfiguration Techniques, Abhishek Dey

Graduate Theses and Dissertations

Reconfigurable radio frequency (RF) devices are attractive for miniaturization of wireless components and systems by handling functionality of multiple distinct devices. Existing reconfiguration techniques rely on device loadings with semiconductor diodes, ferrite/ferroelectric materials, and microelectromechanical system (MEMS) switches and capacitors. However, it is well-recognized that these techniques cannot fully address important system metrics such as high efficiency, wide frequency tuning range, high power handling capability and cost. Therefore, novel alternative techniques are highly desirable to advance the state of the art in reconfigurable RF devices. The aim of this dissertation is to investigate the novel concept of microfluidically loaded ...


Rain Attenuation Effects On Signal Propagation At W/V-Band Frequencies, Nadine Daoud 2016 University of New Mexico

Rain Attenuation Effects On Signal Propagation At W/V-Band Frequencies, Nadine Daoud

Electrical and Computer Engineering ETDs

The current frequency spectrum congestion in space is begging for the exploration and utilization of a new range of frequencies. The W/V-band Terrestrial Link Experiment (WTLE) project run jointly by AFRL, NASA and the University of New Mexico, focuses on using higher frequencies for satellite communications, more precisely, at 72 GHz and 84 GHz.

In this thesis, the rain effect on the propagating signal is studied. First, instantaneous comparisons between the experiment and two different models, the ITU-R and the Siva-Mello, is presented. Second, the WTLE link was analyzed statistically over a period of approximately 10 months, and the ...


Optimal And Miniaturized Strongly Coupled Magnetic Resonant Systems, Hao Hu 2016 Florida International University

Optimal And Miniaturized Strongly Coupled Magnetic Resonant Systems, Hao Hu

FIU Electronic Theses and Dissertations

Wireless power transfer (WPT) technologies for communication and recharging devices have recently attracted significant research attention. Conventional WPT systems based either on far-field or near-field coupling cannot provide simultaneously high efficiency and long transfer range. The Strongly Coupled Magnetic Resonance (SCMR) method was introduced recently, and it offers the possibility of transferring power with high efficiency over longer distances. Previous SCMR research has only focused on how to improve its efficiency and range through different methods. However, the study of optimal and miniaturized designs has been limited. In addition, no multiband and broadband SCMR WPT systems have been developed and ...


Thermoelectric Magnetohydrodynamic Effects In Solidification Processes, Andrew Kao, Koulis Pericleous, Peter Lee, Biao Cai, Jianrong Gao 2016 University of Manchester

Thermoelectric Magnetohydrodynamic Effects In Solidification Processes, Andrew Kao, Koulis Pericleous, Peter Lee, Biao Cai, Jianrong Gao

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Negative Index In Chiral Metamaterials Under Conductive Loss And First-Order Material Dispersion Using Lorentzian, Condon And Drude Models, Monish Ranjan Chatterjee, Tarig A. Algadey 2016 University of Dayton

Negative Index In Chiral Metamaterials Under Conductive Loss And First-Order Material Dispersion Using Lorentzian, Condon And Drude Models, Monish Ranjan Chatterjee, Tarig A. Algadey

Electrical and Computer Engineering Faculty Publications

Emergence of negative index (NIM) in chiral materials with conductive loss using standard dispersive models is reported. Positive and negative phase and group indices are realized as expected for NIM behavior for sidebands with opposite polarities.


Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed 2016 University of Dayton

Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed

Electrical and Computer Engineering Faculty Publications

The effects of turbulence on anisoplanatic imaging are often modeled through the use of a sequence of phase screens distributed along the optical path. We implement the split-step wave algorithm to examine turbulence-corrupted images.


Analysis Of Interference Between Electromagnetic Articulography And Electroglottograph Systems, Kelly Vonderhaar 2016 Marquette University

Analysis Of Interference Between Electromagnetic Articulography And Electroglottograph Systems, Kelly Vonderhaar

Master's Theses (2009 -)

Electromagnetic Articulography (EMA) has become an integral tool for researchers and clinicians who seek to characterize speech kinematics. The position and orientation of the articulators – which include the jaw, lips, and tongue – are recorded by attaching sensors to the articulators and tracking the movement of the sensors through an electromagnetic field. This has been used by researchers and clinicians to better understand dysarthria and synthesize speech, among other applications. Another speech tool, electroglottography (EGG), is used to analyze the movement of the vocal folds during speech production. This is achieved by measuring the time variation of the contact of the ...


Optimization Of The Bowtie Gap Geometry For A Maximum Electric Field Enhancement, Tsenguun Byambadorj 2016 Marquette University

Optimization Of The Bowtie Gap Geometry For A Maximum Electric Field Enhancement, Tsenguun Byambadorj

Master's Theses (2009 -)

Optimization of the geometry of a metallic bowtie gap at radio frequency is presented in this thesis. Since the design and fabrication of a plasmonic device (nanogap) at nanoscale is challenging, the results of this study can be used to estimate the best design parameters for nanogap structure. The geometry of the bowtie gap including gap size, tip width, metal thickness, and tip angle are investigated at macroscale to find the maximum electric field enhancement across the gap. This thesis focuses on the simulation portion of a work that consists of experimental and simulation platforms. The simulation platform is created ...


Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani 2016 Air Force Institute of Technology

Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani

Theses and Dissertations

Achieving worldwide alternatives to GPS is a challenging engineering problem. Current GPS alternatives often suffer from limitations such as where and when the systems can operate. Navigation using the Earth's magnetic anomaly field, which is globally available at all times, shows promise to overcome many of these limitations. We present a navigation filter which uses the Earth's magnetic anomaly field as a navigation signal to aid an inertial navigation system (INS) in an aircraft. The filter utilizes highly-accurate optically pumped cesium (OPC) magnetometers to make scalar measurements of the Earth's magnetic field and compare them to a ...


Optimization-Free Optical Focal Field Engineering Through Reversing The Radiation Pattern From A Uniform Line Source, Yanzhong Yu, Qiwen Zhan 2016 University of Dayton

Optimization-Free Optical Focal Field Engineering Through Reversing The Radiation Pattern From A Uniform Line Source, Yanzhong Yu, Qiwen Zhan

Qiwen Zhan

A simple and flexible method is presented for the generation of optical focal field with prescribed characteristics. By reversing the field pattern radiated from a uniform line source, for which the electric current is constant along its extent, situated at the focus of a 4Pi focusing system formed by two confocal high-NA objective lenses, the required illumination distribution at the pupil plane for creating optical focal field with desired properties can be obtained. Numerical example shows that an arbitrary length optical needle with extremely high longitudinal polarization purity and consistent transverse size of ~0.36λ over the entire depth of ...


Tailoring Optical Complex Fields With Nano-Metallic Surfaces, Guanghao Rui, Qiwen Zhan 2016 University of Dayton

Tailoring Optical Complex Fields With Nano-Metallic Surfaces, Guanghao Rui, Qiwen Zhan

Qiwen Zhan

Recently there is an increasing interest in complex optical fields with spatially inhomogeneous state of polarizations and optical singularities. Novel effects and phenomena have been predicted and observed for light beams with these unconventional states. Nanostructured metallic thin film offers unique opportunities to generate, manipulate and detect these novel fields. Strong interactions between nano-metallic surfaces and complex optical fields enable the development of highly compact and versatile functional devices and systems. In this review, we first briefly summarize the recent developments in complex optical fields. Various nano-metallic surface designs that can produce and manipulate complex optical fields with tailored characteristics ...


Creation Of Identical Multiple Focal Spots With Prescribed Axial Distribution, Yanzhong Yu, Qiwen Zhan 2016 University of Dayton

Creation Of Identical Multiple Focal Spots With Prescribed Axial Distribution, Yanzhong Yu, Qiwen Zhan

Qiwen Zhan

We present a scheme for the construction of coaxially equidistant multiple focal spots with identical intensity profiles for each individual focus and a predetermined number and spacing. To achieve this, the radiation field from an antenna is reversed and then gathered by high numerical aperture objective lenses. Radiation patterns from three types of line sources, i.e., the electric current, magnetic current and electromagnetic current distributions, with cosine-squared taper are respectively employed to generate predominately longitudinally polarized bright spots, azimuthally polarized doughnuts, and focal spots with a perfect spherically symmetric intensity distribution. The required illuminations at the pupil plane of ...


Dynamical Model Of Harmonic Generation In Centrosymmetric Semiconductors At Visible And Uv Wavelengths, Michael Scalora, Maria Antonietta Vincenti, Domenico de Ceglia, N. Akozbek, Vito Roppo, M. J. Bloemer, Joseph W. Haus 2016 Charles M. Bowden Research Center

Dynamical Model Of Harmonic Generation In Centrosymmetric Semiconductors At Visible And Uv Wavelengths, Michael Scalora, Maria Antonietta Vincenti, Domenico De Ceglia, N. Akozbek, Vito Roppo, M. J. Bloemer, Joseph W. Haus

Joseph W Haus

We study second and third harmonic generation in centrosymmetric semiconductors at visible and UV wavelengths in bulk and cavity environments. Second harmonic generation is due to a combination of spatial symmetry breaking, the magnetic portion of the Lorentz force, and quadrupolar contributions from inner core electrons. The material is assumed to have a nonzero, third-order nonlinearity that gives rise to most of the third harmonic signal. Using the parameters of bulk silicon we predict that cavity environments modify the dependence of second harmonic generation on incident angle, while improving third harmonic conversion efficiency by several orders of magnitude relative to ...


Tailoring Metallodielectric Structures For Superresolution And Superguiding Applications In The Visible And Near-Ir Ranges, Domenico de Ceglia, Maria Antonietta Vincenti, M. G. Cappeddu, Marco Centini, Neset Akozbek, Antonella D'Orazio, Joseph W. Haus, Mark J. Bloemer, Michael Scalora 2016 Charles M. Bowden Research Center

Tailoring Metallodielectric Structures For Superresolution And Superguiding Applications In The Visible And Near-Ir Ranges, Domenico De Ceglia, Maria Antonietta Vincenti, M. G. Cappeddu, Marco Centini, Neset Akozbek, Antonella D'Orazio, Joseph W. Haus, Mark J. Bloemer, Michael Scalora

Joseph W Haus

We discuss propagation effects in realistic, transparent, metallodielectric photonic band gap structures in the context of negative refraction and super-resolution in the visible and near infrared ranges. In the resonance tunneling regime, we find that for transverse-magnetic incident polarization, field localization effects contribute to a waveguiding phenomenon that makes it possible for the light to remain confined within a small fraction of a wavelength, without any transverse boundaries, due to the suppression of diffraction. This effect is related to negative refraction of the Poynting vector inside each metal layer, balanced by normal refraction inside the adjacent dielectric layer: The degree ...


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